f a certain cannon is fired from a height of 9.3 meters above the​ ground, at a certain​ angle, the height of the cannonball above the​ ground, h, in​ meters, at​ time, t, in​ seconds, is found by the function h(t) = - 4.9t^2 + 30.5t + 9.3. Find the time it takes for the cannonball to strike the ground.