If you’re not sure which sides to label, pick any corner. Label the three lines that meet at that corner. For example: A box has a base that measures 3 inches by 4 inches, and it stands 5 inches tall. The long side of the base is 4 inches, so l = 4, w = 3, and h = 5.
If you’re not sure which sides to label, pick any corner. Label the three lines that meet at that corner. For example: A box has a base that measures 3 inches by 4 inches, and it stands 5 inches tall. The long side of the base is 4 inches, so l = 4, w = 3, and h = 5.
If you’re not sure which sides to label, pick any corner. Label the three lines that meet at that corner. For example: A box has a base that measures 3 inches by 4 inches, and it stands 5 inches tall. The long side of the base is 4 inches, so l = 4, w = 3, and h = 5.
If you’re not sure which sides to label, pick any corner. Label the three lines that meet at that corner. For example: A box has a base that measures 3 inches by 4 inches, and it stands 5 inches tall. The long side of the base is 4 inches, so l = 4, w = 3, and h = 5.
There are a top and bottom face. Both are the same size. [4] X Research source There are a front and a back face. Both are the same size. There are a left and right face. Both are the same size. If you have trouble picturing this, cut a box apart along the edges and lay it out. [5] X Research source
Going back to our example, the area of the bottom face is 4 inches x 3 inches = 12 square inches.
Going back to our example, the area of the bottom face is 4 inches x 3 inches = 12 square inches.
In our example, the top area is also 12 square inches.
In our example, the top area is also 12 square inches.
In our example, w = 3 inches and h = 5 inches, so the area of the front is 3 inches x 5 inches =15 square inches. The area of the back face is also 15 square inches.
In our example, w = 3 inches and h = 5 inches, so the area of the front is 3 inches x 5 inches =15 square inches. The area of the back face is also 15 square inches.
In our example, w = 3 inches and h = 5 inches, so the area of the front is 3 inches x 5 inches =15 square inches. The area of the back face is also 15 square inches.
In our example, l = 4 inches and h = 5 inches, so the area of the left face = 4 inches x 5 inches = 20 square inches. The area of the right face is also 20 square inches.
In our example, l = 4 inches and h = 5 inches, so the area of the left face = 4 inches x 5 inches = 20 square inches. The area of the right face is also 20 square inches.
In our example, l = 4 inches and h = 5 inches, so the area of the left face = 4 inches x 5 inches = 20 square inches. The area of the right face is also 20 square inches.
To finish our example, just add up all the blue numbers above: 12 + 12 + 15 + 15 + 20 + 20 = 94 square inches.
To finish our example, just add up all the blue numbers above: 12 + 12 + 15 + 15 + 20 + 20 = 94 square inches.
Area of a rectangular prism = 2lw + 2wh + 2lh
Area of a Rectangular Prism = 2lw + 2wh + 2lh = 2(lw + wh + lh).
Area = 2(lw + wh + lh) = 2 x (lw + wh + lh) = 2 x (4x3 + 3x5 + 4x5) = 2 x (12 + 15 + 20) = 2 x (47) = 94 square inches. That’s the same answer we got before. Once you’ve practiced doing these equations, this is a much faster way to find the surface area.
