We can define a rectangle as a four sided quadilateral whose all internal angles are right angles. This is your longest side. Step 1 Add together the area of each side to get the surface area of the box.
The total surface area is then.
This is a rectangle just like every face. 2 3 6 2 2 6 2 2 3 72 cm 2. A 2 450 300 600 A 2 450 300 600. Given below is an illustration of rectangular prism.