Answer:
50; 72; 8; 57.9
Step-by-step explanation:
1. sqrt((30/2)^2 + (20)^2) = sqrt(15^2 + 20^2) = sqrt(225 + 400) = sqrt(625) = 25 (radius) * 2 = 50 (diameter)
2. 360 (degrees in a circle)/5 (sides in a pentagon) = 72 degrees
3. 360 (degrees in a circle)/x (sides) = 45 --> 360/45 = x --> 8 sides = x
4. sqrt(7^2 + (12/2)^2) = radius --> sqrt(49 + 36) --> sqrt85 * 2pi = circumference --> 57.9281062 = circumference --> 57.9
