Three-dimensional objects often combine different two-dimensional shapes. A pyramid is the combination of triangular sides, also called its faces, with a polygonal floor or base. Polygons are closed two-dimensional shapes composed of straight-line segments. The polygonal base affects both the shape and number of the pyramid's faces. When the base is a regular polygon, which is a polygon with equal side lengths, like the square, the faces are identical. You can calculate a square-based pyramid's volume with the formula volume = 1/3 * base area * height, where the height is the perpendicular measurement from the base's center to the object's highest point, known as the apex.
Instructions
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1
Measure one side of the base, then multiply the length by itself. In this example, one side of the base measures 3 inches. Three inches multiplied to itself equals 9 square inches.
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2
Measure the length from the apex to the center of the square base, then multiply that measurement to the base area. In this example, the length from apex to base is 5 inches, and 5 inches multiplied by 9 square inches equals 45 cubic inches.
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3
Divide the product of pyramid's height and base area by 3 to calculate the pyramid's volume. Concluding this example, 45 cubic inches divided by 3 equals 15 cubic inches.