V1 = V2 + 18
V1 =
[tex]3 \times 6 \times x[/tex]
V2 =
[tex] \frac{4 \times 7 \times x}{2} [/tex]
Do the maths...
[tex]3 \times 6 \times x = \frac{4 \times 7 \times x}{2} + 18[/tex]
[tex]18x = 14x + 18[/tex]
[tex]4x = 18[/tex]
[tex]x = 4.5[/tex]
So
The volume of the rectangular prism is 81 cubic feet.
The volume of the triangular prism is 63 cubic feet.
