Question

In a circle, an angle measuring 8.7 radians intercepts an arc of length 3.9. Find the radius of the circle to the nearest 10th.

Answer 1

r = .5 units

Explanation:

8.7 R is an improper FRACTION of the 2 pi R of the entire circle ....set up a ratio:

8.7 / (2 pi) = 3.9 / x where x is the entire circumference measurement

x = 3.9 / (8.7 / (2 pi) ) = 2.82 units

To find the radius circumf = 2 pi r

2.82 = 2 pi r shows r = .5 units