Final answer:
The ball's height is 15 feet at t = 0.54 s and t = 3.79 s.
Step-by-step explanation:
The equation h = 3 + 36t - 16t² represents the height of the ball in feet after t seconds. To find the values of t for which the ball's height is 15 feet, we can set up the equation:
15 = 3 + 36t - 16t²
This is a quadratic equation. To solve for t, we can rearrange the equation to:
16t² - 36t + 12 = 0
Using the quadratic formula, we find that t = 0.54 s and t = 3.79 s are the values for which the ball's height is 15 feet.