Question

2. Find the measure of angle A.

Make sure to show all work.

Answer:

Answer 1

∠A = 80°

Explanation:

The left vertex of the triangle = 4x - 3 ( vertical angles )

The external angle of a triangle is equal to the sum of the 2 opposite interior angles.

125° is an external angle of the triangle, thus

5x + 20 + 4x - 3 = 125, that is

9x + 17 = 125 ( subtract 17 from both sides )

9x = 108 ( divide both sides by 9 )

x = 12

Hence

∠A = 5x + 20 = (5 × 12) + 20 = 60 + 20 = 80°

Answer 2

5x + 20 + 4x - 3 + 55 = 180

9x + 72 = 180

9x= 180 - 72

x= 16.2

5 × 16.2 + 20 = 101

A = 101

sorry wrong answer