Respuesta :

Answer:

b=70

Step-by-step explanation:

The sum of the opposite angles of a triangle is equal to the exterior angle

a+b = 140

We know that a=b since PQ = RQ

The angle  opposite equal sides are equal

Replace a  with b since a =b

b+b = 140

2b = 140

Divide by 2

2b/2 =140/2

b = 70