Im having alot of difficulty with this question, I just cannot get the right answer for this one.

A water trough is 8 m long and its cross-section is an isosceles trapezoid which is 210 cm wide at the bottom and 350 cm wide at the top, and the height is 70 cm. The trough is not full. Give an expression forV, the volume of water in the trough in cm3, when the depth of the water isdcm.

V= ?