Question 697309
Max height is at the vertex:
the time (t) of the vertex is:
t = -b/(2a)
t = -100/(2(-32))
t = -100/(-64)
t = 100/64
t = 25/16 
t = 1.5625 seconds
.
Max height is:
h(t)=100t-16t^2
h(1.5625)=100(1.5625)-16(1.5625)^2
h(1.5625)=156.25-39.0625
h(1.5625)=117.1875 feet