Which triangle is a regular polygon? a) all triangles b) an equiangular triangle c) 45°- 45° - 90° triangle eliminate d) 30°- 60° - 90° triangle

Aball is thrown from a height of 139 feet with an initial downward velocity of 15 ft/s. the ball's height h (in feet) after t seconds is given by the following. h=139-15t-16t^2 how long after the ball is thrown does it hit the ground? round your answer(s) to the nearest hundredth. (if there is more than one answer, use the "or" button.) t =