Answer:
The maximum height reached = 805 feet
Explanation:
The height of the rock in terms of time t is f(t)=−16t²+200t+180
At maximum height f (t) is maximum, at maximum f(t) we have f'(t) = 0
That is
         [tex]f'(t)=0\\\\f'(t)=-32t+200=0\\\\t=6.25s[/tex]
At time t = 6.25 s the rock reaches at maximum height,
Substituting in f(t)
         f(6.25)=−16 x 6.25²+200 x 6.25 +180 = 805 feet
The maximum height reached = 805 feet