How do i do 21? (will mark brainlest for explaining)

This is fractions casey shared a pizza with some friends.they each ate 1 third of the pizza. how many people shared the pizza

In the triangles, tr = ge and sr = fe. if = 3.2 ft, which is a possible measure of ? 1.6 ft 3.0 ft 3.2 ft 4.0 ft

After t seconds, a ball tossed in the air from the ground level reaches a height of h feet given by the equation h = 144t-16t^2. after how many seconds will the ball hit the ground before rebounding?