The equation h (t) = - 16t^2+115t+15 gives the height of a toy rocket, in feet, t seconds after it is launched from a platform.

What is the height of the platform?

The height of the platform is 15.

This equation is in the form

h (t) = - 16t² + v₀t + h₀, where v₀ is the initial velocity and h₀ is the initial height. The number in place of the initial height is 15, so the rocket starts at 15 ft.