Calculating the area of a rectangular prism is very easy to do if you know the width, length, and height. To know how to calculate the area of a rectangular prism, follow the steps below.
Step
Step 1. Determine the length of the prism
Length is the longest side of the rectangular flat surface at the top or bottom of a rectangular prism.
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For example: Length = 5 inches.
Step 2. Determine the width of the prism
Width is the shorter side of the rectangular flat surface at the top or bottom of a rectangular prism.
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For example: Width = 4 inches.
Step 3. Determine the height of the prism
Height is the vertical part of the rectangular prism. Imagine that height is what makes a flat rectangle into a three-dimensional shape.
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For example: Height = 3 inches.
Step 4. Multiply the length, width, and height
Multiply these three values to get the area of the prism. The formula for finding the area of a rectangular prism is: Area = Length * Height * Width, or V = L * H * W.
For example: V = 5 * 4 * 3 = 60 inches
Step 5. Answers must be in cubic units
Since we are calculating area, we are working in three-dimensional space. Add cubic units to the answer. Whether counting in inches, feet, or centimeters, answers must be expressed in cubic units.
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Area 60 will be 60 inches3.
