If a stone is tossed from the top of a 230 meter building; the heigth of as a function of time is given by h(t)=-9.8t^2-10t+230, where t is in seconds, and height is in meters. After how many seconds will the stone hit the ground? Round to the nearest hundreth's place; include units in your answer. Help please.

just solve for h(t) = 0

t = 4.36 sec