Answer:
157 cm
Explanation:
First you need to find the radius so you divide 20 by 2 (20 ÷ 2). Which will give you, our radius of 10. You take that radius and square it so 10 x 10. You will get a product of 100. Then you multiple the 100 by pi (100 x 3.14) and you will get 314. Since it's a semicircle you need to cut this 314 in half (314 ÷ 2 = 157).
