Question

Find the measure of angle A when two angles are congruent?

Answer 1

m∡A = 70º

1) Considering that the Sum of the interior angles within a triangle is always 180º

2) We can write the following, and solve for x

x+80 + x +80 +40 = 180

2x +160 +40 = 180

2x + 200 = 180

2x =180-200

2x= -20

x=-10

3) So since angle A = x +80, we can plug it into that the value of x

m∡A = x +80º

m∡A=-10+80

m∡A = 70º