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
