The ball hits the ground when the height h(t) = 0 , so
-16t^2 + 80t = 0
-16t(t - 5) = 0
t- 5 = 0 or -16t^2 = 0 ( here t = 0 which corresponds to when ball is thrown)
t - 5 = 0 gives:-
t = 5 seconds (answer)
D. 21cm because you divide all sides by 2 then get your slope form and multiply by seven
The answer is 1 : 1 : square root of 3
