SEBA Class 9 Maths Triangles and Quadrilaterals MCQs (2026–27) – Assam Eduverse
The SEBA Class 9 Maths Triangles and Quadrilaterals MCQs are developed in line with the latest ASSEB syllabus and follow the exam pattern of the current academic session. These SEBA Class 9 Maths Triangles and Quadrilaterals MCQs include conceptual, theorem-based, and geometry-focused questions aimed at strengthening students’ understanding of key geometric concepts. For broader coverage, students can also explore important maths MCQs chapter-wise.
Prepared by subject experts of Assam Eduverse, this collection focuses on essential topics such as properties of triangles, angle sum property, congruence, types of quadrilaterals, parallelogram properties, and angle relationships. Practicing triangles and quadrilaterals mcqs class 9 seba along with chapterwise MCQs and question answers helps develop strong geometric reasoning and problem-solving skills.
Consistent revision of these ASSEB class 9 maths important MCQs enhances conceptual clarity and builds confidence for the board examination. Students can also refer to complete Class 9 study materials for comprehensive preparation.
SEBA Class 9 Maths Triangles and Quadrilaterals MCQs – ASSEB Board Exam Practice Questions
Table of Contents
Q1. Line segment joining the mid point of any side with the opposite vertex is:
(a) altitude
(b) median
(c) perpendicular bisector
(d) angle bisector
Answer: (b) median
A median of a triangle is a line segment joining a vertex to the midpoint of the opposite side.
Therefore, the correct answer is median.
Q2. The length of perpendicular drawn from the opposite vertex to any side is:
(a) altitude
(b) median
(c) perpendicular bisector
(d) angle bisector
Answer: (a) altitude
An altitude is a perpendicular drawn from a vertex to the opposite side.
Hence, the required length is called altitude.
Q3. The point of intersection of all the altitudes of a triangle is:
(a) orthocentre
(b) incentre
(c) circumcentre
(d) centroid
Answer: (a) orthocentre
All three altitudes of a triangle meet at one point called the orthocentre.
So, the correct answer is orthocentre.
Q4. The point of intersection of the perpendicular bisector of all sides of a triangle is:
(a) orthocentre
(b) incentre
(c) circumcentre
(d) centroid
Answer: (c) circumcentre
The perpendicular bisectors of the sides of a triangle meet at one point called the circumcentre.
Hence, the answer is circumcentre.
Q5. In a triangle, the angle opposite to the longest side is:
(a) greater than 60°
(b) measure of 50°
(c) greater than 90°
(d) none of these
Answer: (d) none of these
In a triangle, the largest angle lies opposite the longest side.
But its measure depends on the type of triangle. It is not always greater than 60° or 90°.
Therefore, the correct answer is none of these.
Q6. The point of intersection of all the medians of a triangle is:
(a) orthocentre
(b) incentre
(c) circumcentre
(d) centroid
Answer: (d) centroid
All three medians of a triangle intersect at a point called the centroid.
Hence, the answer is centroid.
Q7. In a triangle ABC, if 2∠A = 3∠B = 6∠C, then the measure of ∠A is:
(a) 30°
(b) 75°
(c) 90°
(d) 60°
Answer: (c) 90°
Let 2A = 3B = 6C = k.
Then A = k/2, B = k/3, C = k/6.
A + B + C = 180°
k/2 + k/3 + k/6 = 180°
(3k + 2k + k)/6 = 180°
6k/6 = 180°
k = 180°
A = k/2 = 90°.
Q8. In a triangle ABC, if 2∠A = 3∠B = 6∠C, then the measure of ∠B is:
(a) 30°
(b) 75°
(c) 90°
(d) 60°
Answer: (d) 60°
From previous result, k = 180°.
B = k/3 = 60°.
Q9. In a triangle ABC, if 2∠A = 3∠B = 6∠C, then the measure of ∠C is:
(a) 30°
(b) 75°
(c) 90°
(d) 60°
Answer: (a) 30°
C = k/6 = 180°/6 = 30°.
Q10. In a triangle ABC, if ∠A − ∠B = 33° and ∠B − ∠C = 18°, then the measure of ∠A is:
(a) 88°
(b) 55°
(c) 37°
(d) 60°
Answer: (a) 88°
Let C = x.
Then B = x + 18°.
A = B + 33° = x + 51°.
A + B + C = 180°
(x + 51) + (x + 18) + x = 180°
3x + 69 = 180°
3x = 111°
x = 37°.
A = x + 51 = 88°.
Q11. In a triangle ABC, if ∠A − ∠B = 33° and ∠B − ∠C = 18°, then the measure of ∠B is:
(a) 88°
(b) 55°
(c) 37°
(d) 60°
Answer: (b) 55°
From previous calculation, C = 37°.
B = C + 18° = 55°.
Q12. In a triangle ABC, if ∠A − ∠B = 33° and ∠B − ∠C = 18°, then the measure of ∠C is:
(a) 88°
(b) 55°
(c) 37°
(d) 60°
Answer: (c) 37°
From solving the equations, C = 37°.
Q13. In a triangle ABC, if ∠A + ∠B = 65° and ∠B + ∠C = 140°, then the measure of ∠A is:
(a) 40°
(b) 25°
(c) 115°
(d) 60°
Answer: (a) 40°
A + B = 65°
B + C = 140°
Adding:
A + 2B + C = 205°
But A + B + C = 180°
Subtracting:
B = 25°
Then A = 65 − 25 = 40°.
Q14. In a triangle ABC, if ∠A + ∠B = 65° and ∠B + ∠C = 140°, then the measure of ∠B is:
(a) 40°
(b) 25°
(c) 115°
(d) 60°
Answer: (b) 25°
From previous calculation, B = 25°.
Q15. In a triangle ABC, if ∠A + ∠B = 65° and ∠B + ∠C = 140°, then the measure of ∠C is:
(a) 40°
(b) 25°
(c) 115°
(d) 60°
Answer: (c) 115°
C = 180° − (A + B)
C = 180° − 65° = 115°.
Q16. The bisectors of angles of a parallelogram form a :
(a) trapezium
(b) rectangle
(c) rhombus
(d) kite
Answer: (b) rectangle
In a parallelogram, adjacent angles are supplementary (sum = 180°).
Their angle bisectors therefore meet at right angles.
Hence, the figure formed by the bisectors is a rectangle.
Q17. The angles of a quadrilateral are in the ratio 3 : 4 : 5 : 6. The respective angles of the quadrilateral are:
(a) 60°, 80°, 100°, 120°
(b) 120°, 100°, 80°, 60°
(c) 120°, 60°, 80°, 100°
(d) 80°, 100°, 120°, 60°
Answer: (a) 60°, 80°, 100°, 120°
Sum of angles of a quadrilateral = 360°.
3x + 4x + 5x + 6x = 18x = 360°
x = 20°
Angles are 60°, 80°, 100°, 120°.
Q18. If diagonals of a quadrilateral are equal and bisect each other at right angles, then it is a:
(a) parallelogram
(b) square
(c) rhombus
(d) trapezium
Answer: (b) square
If diagonals are equal, bisect each other and are perpendicular, the quadrilateral is a square.
Hence, the answer is square.
Q19. If in rectangle ABCD, diagonal AC bisects ∠A as well ∠C, then ABCD is a:
(a) parallelogram
(b) square
(c) rhombus
(d) trapezium
Answer: (b) square
In a rectangle, diagonals are equal.
If a diagonal also bisects the angles, then all sides are equal.
So the rectangle becomes a square.
Q20. The line segment joining the midpoints of two sides of a triangle is parallel to the third side and ________ of it.
(a) half
(b) one third
(c) one fourth
(d) equal
Answer: (a) half
By Mid-point Theorem, the line joining midpoints of two sides of a triangle is parallel to the third side and half of its length.
Q21. Line segment joining the midpoints of the opposite sides of a quadrilateral ________ each other.
(a) trisect
(b) bisect
(c) coincide
(d) none of these
Answer: (b) bisect
The line segments joining midpoints of opposite sides of a quadrilateral bisect each other.
Q22. Three angles of a quadrilateral are 75°, 90° and 75°. The fourth angle is:
(a) 90°
(b) 95°
(c) 105°
(d) 120°
Answer: (d) 120°
Sum of angles = 360°.
75 + 90 + 75 = 240°
Fourth angle = 360 − 240 = 120°.
Q23. A diagonal of a rectangle is inclined to one side of the rectangle at 25°. The acute angle between the diagonals is:
(a) 55°
(b) 50°
(c) 40°
(d) 25°
Answer: (b) 50°
If diagonal makes 25° with a side, then the other diagonal makes 25° on the other side.
Acute angle between diagonals = 2 × 25° = 50°.
Q24. ABCD is a rhombus such that ∠ACB = 40°, then ∠ADB =
(a) 45°
(b) 50°
(c) 40°
(d) 60°
Answer: (c) 40°
In a rhombus, diagonals bisect the angles.
So ∠ACB = 40° means angle at C is 80°.
Opposite angles are equal, so angle at D is 80°.
Diagonal BD bisects angle D.
Thus ∠ADB = 40°.
Q25. The quadrilateral formed by joining the midpoints of the sides of a quadrilateral PQRS, taken in order, is a rectangle, if
(a) PQRS is a rectangle
(b) PQRS is a parallelogram
(c) diagonals of PQRS are perpendicular
(d) diagonals of PQRS are equal
Answer: (c) diagonals of PQRS are perpendicular
The quadrilateral formed by joining midpoints is always a parallelogram.
It becomes a rectangle when the diagonals of the original quadrilateral are perpendicular.
Q26. The quadrilateral formed by joining the midpoints of the sides of a quadrilateral PQRS, taken in order, is a rhombus, if
(a) PQRS is a rhombus
(b) PQRS is a parallelogram
(c) diagonals of PQRS are perpendicular
(d) diagonals of PQRS are equal
Answer: (d) diagonals of PQRS are equal
The midpoint quadrilateral becomes a rhombus when diagonals of original quadrilateral are equal.
Q27. If angles A, B, C and D of the quadrilateral ABCD, taken in order are in the ratio 3:7:6:4, then ABCD is a
(a) parallelogram
(b) kite
(c) rhombus
(d) trapezium
Answer: (a) parallelogram
Let angles be 3x, 7x, 6x, 4x.
3x + 7x + 6x + 4x = 20x = 360°
x = 18°
Angles are 54°, 126°, 108°, 72°.
Opposite angles are supplementary, hence ABCD is a parallelogram.
Q28. The bisectors of angles of a parallelogram form a :
(a) trapezium
(b) rectangle
(c) rhombus
(d) kite
Answer: (b) rectangle
In a parallelogram, adjacent angles are supplementary (sum = 180°).
Their angle bisectors therefore meet at right angles.
Hence, the figure formed by the bisectors is a rectangle.
Q29. The angles of a quadrilateral are in the ratio 3 : 4 : 5 : 6. The respective angles of the quadrilateral are:
(a) 60°, 80°, 100°, 120°
(b) 120°, 100°, 80°, 60°
(c) 120°, 60°, 80°, 100°
(d) 80°, 100°, 120°, 60°
Answer: (a) 60°, 80°, 100°, 120°
Sum of angles of a quadrilateral = 360°.
3x + 4x + 5x + 6x = 18x = 360°
x = 20°
Angles are 60°, 80°, 100°, 120°.
Q30. If diagonals of a quadrilateral are equal and bisect each other at right angles, then it is a:
(a) parallelogram
(b) square
(c) rhombus
(d) trapezium
Answer: (b) square
If diagonals are equal, bisect each other and are perpendicular, the quadrilateral is a square.
Hence, the answer is square.
Q31. If in rectangle ABCD, diagonal AC bisects ∠A as well ∠C, then ABCD is a:
(a) parallelogram
(b) square
(c) rhombus
(d) trapezium
Answer: (b) square
In a rectangle, diagonals are equal.
If a diagonal also bisects the angles, then all sides are equal.
So the rectangle becomes a square.
Q32. The line segment joining the midpoints of two sides of a triangle is parallel to the third side and ________ of it.
(a) half
(b) one third
(c) one fourth
(d) equal
Answer: (a) half
By Mid-point Theorem, the line joining midpoints of two sides of a triangle is parallel to the third side and half of its length.
Q33. Line segment joining the midpoints of the opposite sides of a quadrilateral ________ each other.
(a) trisect
(b) bisect
(c) coincide
(d) none of these
Answer: (b) bisect
The line segments joining midpoints of opposite sides of a quadrilateral bisect each other.
Q34. Three angles of a quadrilateral are 75°, 90° and 75°. The fourth angle is:
(a) 90°
(b) 95°
(c) 105°
(d) 120°
Answer: (d) 120°
Sum of angles = 360°.
75 + 90 + 75 = 240°
Fourth angle = 360 − 240 = 120°.
Q35. A diagonal of a rectangle is inclined to one side of the rectangle at 25°. The acute angle between the diagonals is:
(a) 55°
(b) 50°
(c) 40°
(d) 25°
Answer: (b) 50°
If diagonal makes 25° with a side, then the other diagonal makes 25° on the other side.
Acute angle between diagonals = 2 × 25° = 50°.
Q36. ABCD is a rhombus such that ∠ACB = 40°, then ∠ADB =
(a) 45°
(b) 50°
(c) 40°
(d) 60°
Answer: (c) 40°
In a rhombus, diagonals bisect the angles.
So ∠ACB = 40° means angle at C is 80°.
Opposite angles are equal, so angle at D is 80°.
Diagonal BD bisects angle D.
Thus ∠ADB = 40°.
Q37. The quadrilateral formed by joining the midpoints of the sides of a quadrilateral PQRS, taken in order, is a rectangle, if
(a) PQRS is a rectangle
(b) PQRS is a parallelogram
(c) diagonals of PQRS are perpendicular
(d) diagonals of PQRS are equal
Answer: (c) diagonals of PQRS are perpendicular
The quadrilateral formed by joining midpoints is always a parallelogram.
It becomes a rectangle when the diagonals of the original quadrilateral are perpendicular.
Q38. The quadrilateral formed by joining the midpoints of the sides of a quadrilateral PQRS, taken in order, is a rhombus, if
(a) PQRS is a rhombus
(b) PQRS is a parallelogram
(c) diagonals of PQRS are perpendicular
(d) diagonals of PQRS are equal
Answer: (d) diagonals of PQRS are equal
The midpoint quadrilateral becomes a rhombus when diagonals of original quadrilateral are equal.
Q39. If angles A, B, C and D of the quadrilateral ABCD, taken in order are in the ratio 3:7:6:4, then ABCD is a
(a) parallelogram
(b) kite
(c) rhombus
(d) trapezium
Answer: (a) parallelogram
Let angles be 3x, 7x, 6x, 4x.
3x + 7x + 6x + 4x = 20x = 360°
x = 18°
Angles are 54°, 126°, 108°, 72°.
Opposite angles are supplementary, hence ABCD is a parallelogram.
Q40. Given four points A, B, C, D such that three points A, B, C are collinear. By joining these points in order, we get
(a) a straight line
(b) a triangle
(c) quadrilateral
(d) none of these
Answer: (d) none of these
Since A, B and C lie on the same straight line, joining them with D does not form a proper quadrilateral.
Q41. In quadrilateral ABCD, AB = BC and CD = DA, then the quadrilateral is a
(a) parallelogram
(b) rhombus
(c) kite
(d) trapezium
Answer: (c) kite
A quadrilateral with two pairs of adjacent equal sides is called a kite.
Q42. Given a triangular prism, then what can we conclude about the lateral faces.
(a) faces are rectangular
(b) faces are parallelogram
(c) faces are trapeziums
(d) square
Answer: (b) faces are parallelogram
In any prism, lateral faces are parallelograms.
Hence, triangular prism has parallelogram lateral faces.
Q43. The bisectors of the angles of parallelogram enclose a
(a) parallelogram
(b) rhombus
(c) rectangle
(d) square
Answer: (c) rectangle
Adjacent angles of a parallelogram are supplementary (180°).
Their bisectors meet at right angles.
Hence, they form a rectangle.
Q44. Which if the following quadrilateral a rhombus?
(a) diagonals bisect each other
(b) all the four sides are equal
(c) diagonals bisect opposite angles
(d) one angle between the diagonals is 60°
Answer: (b) all the four sides are equal
A rhombus is a quadrilateral in which all four sides are equal.
Q45. Consecutive angles of parallelogram are
(a) equal
(b) supplementary
(c) complementary
(d) none of these
Answer: (b) supplementary
Sum of consecutive angles in a parallelogram is 180°.
Hence, they are supplementary.
Q46. Given a rectangle ABCD and P, Q, R, S midpoints of AB, BC, CD and DA respectively.
(a) parallelogram with adjacent sides 4 cm
(b) rectangle with adjacent sides 4 cm
(c) rhombus with side 4 cm
(d) square with side 4 cm
Answer: (c) rhombus with side 4 cm
Joining midpoints of a rectangle forms a rhombus whose sides equal half of the diagonal.
Q47. In parallelogram ABCD, bisectors of angles A and B intersect at O. Find ∠AOB.
(a) 30°
(b) 60°
(c) 90°
(d) 120°
Answer: (c) 90°
Adjacent angles of a parallelogram are supplementary. Their bisectors meet at 90°.
Q48. If an angle of a parallelogram is two-third of its adjacent angle, the smallest angle is
(a) 108°
(b) 54°
(c) 72°
(d) 81°
Answer: (c) 72°
Let larger angle = x.
Smaller angle = (2/3)x.
x + (2/3)x = 180° → x = 108°.
Smallest angle = 72°.
Q49. If the degree measures of the angles of quadrilateral are 4x, 7x, 9x and 10x, what is the sum of the smallest and largest angle?
(a) 140°
(b) 150°
(c) 168°
(d) 180°
Answer: (c) 168°
4x + 7x + 9x + 10x = 30x = 360°
x = 12°
Smallest = 48°, Largest = 120°
Sum = 168°.
SEBA Class 9 Maths Triangles and Quadrilaterals MCQs – Important Objective Questions
A strong understanding of Triangles and Quadrilaterals is essential for mastering geometry and developing logical problem-solving skills. Practicing MCQs based on the latest SEBA (ASSEB) syllabus helps students build clear concepts while becoming familiar with the types of objective questions asked in examinations.
These SEBA Class 9 Maths Triangles and Quadrilaterals MCQs cover important topics such as angle sum property of triangles, congruence of triangles, properties of parallelograms, different types of quadrilaterals, and relationships between angles and sides. Since many geometry questions are theorem-based, regular practice helps students understand and apply these concepts more effectively.
Solving such important objective questions for Class 9 Maths improves logical reasoning and helps students analyze geometric figures with better accuracy. It also strengthens their understanding of properties and theorems, making it easier to solve both objective and descriptive questions.
Consistent practice enhances accuracy, speed, and confidence, enabling students to approach exam questions more efficiently. It also supports quick revision and better retention of key concepts before tests and final assessments.
To perform well in school exams and board-based assessments, students should regularly revise and practice these MCQs. With strong conceptual clarity and continuous practice, this chapter becomes easier to understand and score high in.
FAQs – SEBA Class 9 Maths Triangles and Quadrilaterals MCQs
1. Are SEBA Class 9 Maths Triangles and Quadrilaterals MCQs important for final exam?
Yes, very important. Around 45 MCQs are expected in the latest ASSEB exam pattern. Practice regularly to improve speed and accuracy.
2. Where can I download SEBA Class 9 Maths Triangles and Quadrilaterals MCQs with answers?
You can find free PDFs on Assam Eduverse and similar sites. Always choose chapter-wise MCQs with solutions for better understanding.
3. Which topics are most important in Triangles and Quadrilaterals for MCQs?
Focus on triangle congruence, angle properties, and types of quadrilaterals. These concepts are frequently repeated in MCQs.
4. Is Triangles and Quadrilaterals chapter difficult for SEBA Class 9 students?
Not really difficult. It becomes easy with diagrams and practice. Start with basics, then solve MCQs to build confidence.
5. How to prepare SEBA Class 9 Maths MCQs for better marks in exams?
Practice daily MCQs, revise formulas, and solve previous year questions. Assam Eduverse mock tests can help improve exam performance.
6. Do SEBA exams repeat MCQs from previous years in Maths?
Yes, similar questions often repeat. Solving past MCQs helps you recognize patterns and score quickly in the exam.
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