algebra
posted by alexis .
the formula d=(square root)12,800+h^2 gives the distance d in kilometers to the horizon from a satellite h kilometers above Earth.Find the distance to the horizon to the horizon from a satellite 4200 km above Earth. Round to the nearest kilometer. PLEASE HELP ME

what's the problem? you are given a formula and a value. Plug the value into the formula.
d(h) = √(12800 + h^2)
d(4200) = √(12800+4200^2)
= √(12800+17640000)
= √17652800
= 4201