Arectangle pyramid fits exactly on top of a rectangular prism. the prism has a length of 18 cm, a width of 6 cm, and a height of 9 cm. the pyramid has a height of 15 cm. find the volume of the composite space figure

To find the volume of the prism you are going to use the formula  V=WxLxH.
When you plug in your numbers you should get V= 18x6x9 which ends up equaling 972.

Now that you have that you need to find the volume of the pyramid using the formula V= L x W x H /3 and when you plug that in it looks like
V= 18 x 6 x 15 /3

Upon simplifying that you get 540.

Now you have the volume of your rectangular prism and your rectangular pyramid add them together and you should get 1512

I recommend drawing it out... it helps a lot:)