If m za = 87º and mzb = 32°, find m21.

Step-by-step explanation:

∠1 = ∠A + ∠B          

                 { exterior angle equals the sum of opposite interior angles }

    = 87 + 32

     = 119

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6