Question

How do i set it up ?

Answer 1

m∠A = m∠D = 40°

Explanation:

Angles A and D are corresponding angles in the congruent triangles, so have the same measure. You set one measure equal to the other:

x + 20 = 2x

To solve this, subtract x from both sides:

20 = x

Then both angle measures are 2x = 40°.