Page 1 - WORKSHEET-1 CH-7 TRIANGLES

SAI INTERNATIONAL SCHOOL
Class: IX
Mathematics
Worksheet -1

TOPIC: CONGRUENCY OF TRIANGLES (SAS, ASA, AAS CONGRUENCY)

1. In ∆ABC, BC = AB and ∠B = 80°. Then, ∠A is equal to 1
(a) 80° (b) 40° (c) 50° (d) 100°

2. It is given that ∆ABC ≅ ∆FDE and AB = 5 cm, ∠B = 40° and ∠A = 80°. Then, 1
which of the following is true?
(a) DF = 5 cm, ∠F = 60° (b) DF = 5 cm, ∠E = 60°
(c) DE = 5 cm, ∠E = 60° (d) DE = 5 cm, ∠D = 60°

3. In triangles ABC and DEF, AB = FD and ∠A = ∠D. The two triangles will 1
be congruent by SAS axiom. Then,
(a) BC = EF (b) AC = DE (c) AC = EF (d) BC = DE

4. Difference of two sides of a triangle is ______than the third side. 1

5. In triangles ABC and PQR, AB = AC, ∠C = ∠P and ∠B = ∠Q. The two 1
triangles are ________________________.

6. It is given that ∆ABC ≅ ∆RPQ. Is it true to say that BC = QR? Why? 1

7. Which of the following is not a criterion for congruence of triangles? 1
(a) SAS (b) ASA (c) SSA (d) SSS

8. In a Δ ABC, if ∠A = 120° and AB = AC. Find ∠B and ∠C 2

9. Two lines AB and CD intersect at O such that BC is equal and parallel to AD. 2
Prove that the lines AB and CD bisect at O.

10. In a Δ ABC, if AB = AC and ∠ B = 70°, find ∠ A. 2

11. If the bisector of the exterior vertical angle of a triangle be parallel to the base. 3
Show that the triangle is isosceles.

12. PQR is a triangle in which PQ = PR and is any point on the side PQ. Through S, 3
a line is drawn parallel to QR and intersecting PR at T. Prove that PS = PT.

13. In an isosceles triangle, if the vertex angle is twice the sum of the base angles, 3
calculate the angles of the triangle.