Question

The perimeter of a semicircle is 5.14 millimeters what is the semicircle diameter

Answer 1

2 mm

Explanation:

let the radius of the semi-circle be r

Then,

length of curved portion = 1/2 x circumference = (1/2) (2)(π)r = πr

length of straight portion = diameter of circle = 2r

Hence, we can write an expression for the perimeter

Perimeter = length of curved portion + length of straight portion

Perimeter = πr + 2r

Perimeter = (π + 2)r

since we are given the perimeter = 5.14, assuming that π=3.14, our equation becomes:

5.14 = (3.14 + 2)r

5.14 = 5.14 r

r = 5.14 / 5.14 = 1

Hence, diameter = 2r = 2(1) = 2 mm