Class 9 • Maths • Chapter 7
TRIANGLES
True & False Quiz
Congruent. Criteria. Prove.
✓True
✗False
25
Questions
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Ch.7
Chapter
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IX
Class
Why True & False for TRIANGLES?
How this format sharpens your conceptual clarity
🔵 Triangle congruence is the cornerstone of Euclidean geometry proofs — every geometric theorem about quadrilaterals, circles, and similarity traces back to it.
✅ T/F tests the five congruence criteria (SAS, ASA, SSS, RHS, AAS), CPCT, and inequalities in triangles.
🎯 SSA (Side-Side-Angle) is NOT a valid congruence criterion — a frequently tested false statement.
📋
Read each statement carefully. Click True or False — instant feedback with explanation appears. Submit anytime; unattempted questions are marked Skipped.
Q 1
The sum of the interior angles of any triangle is always 180°.
Q 2
All sides of an scalene triangle are equal.
Q 3
In an isosceles triangle, two angles are always equal.
Q 4
The exterior angle of a triangle is always greater than any interior angle.
Q 5
Triangle ABC with sides 2 cm, 3 cm, and 9 cm can be constructed.
Q 6
A triangle can have more than one right angle.
Q 7
In a right triangle, the hypotenuse is the longest side.
Q 8
Congruent triangles may have different sizes but identical shapes.
Q 9
All equilateral triangles are also isosceles.
Q 10
Two triangles with equal areas are always congruent.
Q 11
The perimeter of a triangle is always less than the sum of two of its sides.
Q 12
If two triangles have three pairs of equal angles, they are congruent.
Q 13
The ASA criterion proves triangle congruence.
Q 14
All sides of a right triangle are equal in length.
Q 15
The centroid of a triangle is the intersection of its medians.
Q 16
The orthocentre of a triangle always lies within the triangle.
Q 17
SSS is a criterion to prove triangle congruence.
Q 18
An obtuse triangle cannot be equilateral.
Q 19
If two sides of one triangle and two sides of another triangle are equal, triangles are congruent.
Q 20
All triangles can be inscribed in a circle.
Q 21
In an isosceles triangle, the perpendicular from the vertex to the base bisects the base.
Q 22
Two right triangles with equal hypotenuse and one side are always congruent.
Q 23
Any triangle can have two equal sides.
Q 24
In a triangle, the sum of any two interior angles is greater than the third angle.
Q 25
The angle bisectors of a triangle always meet at a point inside the triangle.
Key Takeaways — TRIANGLES
Core facts for CBSE Boards & exams
1
Congruence criteria: SAS, ASA, AAS, SSS, RHS — all valid. SSA is NOT valid.
2
CPCT: Corresponding Parts of Congruent Triangles are equal.
3
Angles opposite equal sides are equal; sides opposite equal angles are equal.
4
In a triangle, greater angle is opposite the greater side.
5
Sum of any two sides of a triangle is GREATER than the third side (triangle inequality).
6
Exterior angle = sum of two non-adjacent interior angles.