The radius of a semi circle is 2 km. What is the semi circles perimeter? Use 3.14 The radius of a semi circle is 2 km. What is the semi circles perimeter? Use 3.14 for pi

Answer 1

1. First, modify the formula for the circumference of a circle to reflect that you are dealing with a semicircle. The formula for the circumference of a circle (C) is as follows:
2. C = 2 x pi x radius (r)
3. Since a semicircle is one half of a circle, the circumference of a semicircle is half the circumference of a circle. The formula for the circumference of a semicircle (SC) is the formula for the circumference of a circle multiplied by one half, or 0.5.
4. SC = 0.5 x 2 x pi x r
5. Since 0.5 x 2 = 1, you can write the equation this way:
6. SC = pi x r
7. Now solve the equation for r, since you are trying to solve for radius. Do this by dividing both sides by pi to get r by itself. The result is the following:
8. r = SC ÷ pi
9. Finally, plug in the value you have been given for the circumference of the semicircle and the value of pi to calculate the radius. For example, if the semicircle has a circumference of 2km , the calculation would look like this:
10. r = 2 km ÷ 3.14 = .6369 km