So,
A composite figure is a figure composed of multiple figures.
We'll make it simple and just use two figures, a cube and a rectangular prism.
Our cube will be 9 x 9 x 9 units, making it have a volume of 729 cubic units.
Our rectangular prism will be 2 x 10 x 7, making it have a volume of 140 cubic units.
Combining them, we will get a composite figure of 869 cubic units.