Question

The diameter of a semicircle is 10 meters. What is the perimeter of the semicircle, in meters? Round your answer to the nearest tenth.

Answer 1

25.7 m

Explanation:

The formula for the circumference of a circle is C = 2(pi)(r), where r is the radius, which in turn is half the diameter. Thus, the formula for the circumference is C = (d)(pi). The perimeter of a semicircle is half that, or

C = (pi)(r), which here is (3.14)(5 m) = 15.7 m. Finally, the total perimeter is the sum of this 15.7 m and the 10 m diameter of the circle:

P = 15.7 m + 10 m = 25.7 m