in triangle ABC and PQR, AB=AC,angle C= angle P and angle B=angle Q.THE two triangle are:

In triangle ABC and PQR, AB = AC. angle C = angle P and angle B = angle Q.

In such case these triangles are called isosceles triangles.

The reason is described below.

 

In triangle ABC; AB = AC.

So, triangle ABC is an isosceles triangle.

 

It is given that

Angle C = angle P                                               … (1)

Angle B = angle Q.                                              … (2)

 

Given that in triangle ABC; AB = AC.

So, angle B = angle C                                        … (3)

 

From (1), (2) and (3);

Angle P = angle Q

 

So, PR = QR in triangle PQR.

 

This shows that the triangle PQR is an isosceles triangle.