how to find area of rectangular prism
SA = $94\mbox{ cm}^2$. Example 2. Find the surface area for this rectangular prism. SA = 2 â¢ Top + 2 â¢ Front + 2 â¢ Left. SA = 2lw + 2lh + 2wh. SA = 2 â¢ 6 â¢ 3 + 2 â¢ 6 â¢ 3 + 2 â¢ 3 â¢ 3. SA = 36 + 36 + 18. SA = $90\mbox{ cm}^2$. Example 3. Find the surface area for this rectangular prism. SA = 2 â¢ Top + 2 â¢ Front + 2 â¢ Left. SA = 2lw + 2lh + 2wh. SA = 2 â¢ 5 â¢ 4 + 2 â¢ 5 â¢ 7 + 2 â¢ 4 â¢ 7. SA = 40 + 70 + 56. SA = $166\mbox{ cm}^2$. Geogebra applet: Use the length, width, and height sliders to create a rectangular prism of your choosing.