There are 400 students in a school. In Zachary's class, 18 out of 30 students participate in after-school activities. Based on Zachary's class, about how many students in the school are predicted to participate in after-school activities?
Area = area of the square in the center + 2 * area of the 2 quarter circles.
= 5^2 + 2 * 1/4 *3.14 * 5^2
= 25 + 39.25
= 64.3 in^2 answer