Each number sentence in Exercises 29-31 is a model for the surface area of a three-dimensional figure. Identify which three-dimensional figure the
number sentence describes. Find the surface area.
29. 2 x (4) + 2 x (8.5) + 2 x (7.25)
30. 2 x (4 + 8.5 + 7.25)
31. 27 x (4)2 + 211 (4)(8.5)

The graph below shows the amount of money left in the school’s desk fund, f, after d desks have been purchased. for each new desk that is purchased, by how much does the amount of money left in the school’s desk fund decrease?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.

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 =