Question

a+b= 70
b+c = 130
a=? ?​

Answer 1

Given:

a + b = 70°

b + c = 130°

We know that

a + b + c = 180°

In other words :

Whole of a triangle is 180°

Step-by-step explanation:

(a+b) 70° + c = 180°

∠C = (180 - 70)° = 110°

(b+c) 130° + a = 180°

∠A = (180 - 130)° = 50°

∠B = 180° - (110 + 50)° = 120°

Answer:

∠B = 120°

Hope this helps