Question 999806
The maximum height is reacer when its speed is zero, so take the derivative and set it equal to zero to find out when, then plug that time into h(t)...
h'(t) = -32t + 200 = 0
t = 6.25 seconds
h(6.25) = -16(6.25)^2 + 200(6.25)+100 = 725 feet