Hi Taylor Lynn,
I found an equation which should be what you need:
The velocity (v) at splat time is the square root of twice the acceleration of gravity (g) multiplied by the distance fallen (h). Or,
v = sqrt (2 x g x h). So,
v^2 = 2 x g x h, and then solving for h,
h = v^2/2g
acceleration of gravity = 32.2 feet per second per second = 32.2 ft/s/s, and the velocity you are given is 84 ft/s. So, if h = v^2/2g, then
h = (84 x 84)/64.4
h = 109.57 feet
Note also, this equation does not take into account air friction.
http://www.angio.net/personal/climb/speed
http://www.school-for-champions.com/science/gravity_equations_falling_velocity.htm#.WBwJKSgQifQ