Answer:
1. Isosceles Triangle
2. ∠D = 160°
Step-by-step explanation:
1.
7x + 5 + x + 20 + 2x + 5 = 180 (all angles in a triangle add up to 180)
10x = 150
x = 15°
∠A = 7x + 5
sub x = 15°
∠A = 7x + 5
∠A = 120°
∠B = x + 20
x = 15
∠B = 35
∠C = 2x + 5
x = 15
∠C = 35
Base angles are the same, so this triangle is isosceles
2.
3x + (2x - 1) + (x + 3) + (3x - 3) + (x - 2) = 540 (all angles in a 5-sided polygon equals 540°)
10x = 540 + 1 - 3 + 3 + 2
10x = 543
x = 54.3
∠D = 3x - 3
x = 54.3
∠D = 159.9
if you round it, it would about 160°
