If a stone is tossed from the top of a 210 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 210, where t is in seconds, and height is in meters. After how many seconds will the stone hit the ground? Round to the nearest hundredth’s place; include units in your answer.

set

0 = -9.8t^2 - 10t + 210

use the quadratic formula, where
a = -9.8
b = -10
c = 210

I got 4.14 seconds