2. What is the radius of a circle if the length of a 45° arc is 9?

Answer: 11.46

Step-by-step explanation:

Formula for calculating the length of an arc is theta/360 * 2Πr. Where;

length of the arc (L) = 9

Theta = 45°

L = theta/360 * 2Πr

9 = 45/360 * 2Πr

9 = 1/8 * 2Πr

9 = Πr/4

Πr = 36

r = 36/Π

r = 11.46

Substituting we have,

9 = r * 45°

r = 9/45