A ball is thrown in the air from the top of a building. Its height, in meters above ground, as a function of time, in seconds, is given by h(t) = −4.9t^2 + 18t + 15. How long does it take to reach maximum height? (Round your answer to three decimal places.)

The surface area of the triangular prism is .

Adecorative window is made up of a rectangle with semicircles at either end. the ratio of ad to ab is 3: 2 and ab is 30 inches. what is the ratio of the area of the rectangle to the combined area of the semicircles? possible answers: a. 2: 3 b. 3: 2 c. 6: π d. 9: π e. 30: π

Two numbers have a sum of -19. one number is x. what expression represents the other number?