A trough is 9 feet long and

foot high. The vertical cross-section of the trough parallel to an end is shaped like the graph of

from

to

. The trough is full of water. Find the amount of work required to empty the trough by pumping the water over the top. Note: The weight of water is 62 pounds per cubic foot.

I understand how to do these problems in general but how can you find the volume if not given the width?I guess I don't understand what "vertical cross-section of the trough parallel to an end" means.....