The time (t, in seconds) for a free-falling object to fall d feet is described by the mathematical formula:

Question

t=d over the square root of 16

If a worker accidentally drops a hammer from a building and it hit the ground 4 seconds later, from what height was the hammer dropped

Answer 1

sqrt(16)=4
t=d/4
t=4
4=d/4
d=16
the hammar was dropped from 16 feet

Answer 2

your formula for time should have been:
t = √(d/16) or d = 16t^2

when t=4, then
d = 16(4^2) = 64 feet