You will use the formula V = Bh, where B is the area of the base of the prism.
In this case use the formula for area of a trapezoid. A = 1/2 h (b1 + b2)
V = Bh
V = 1/2 x 3 x (2 + 5) x 10
V = 105 cubic cm
The volume of the prism is 105 cubic centimeters.