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Volumes of Prisms and Surface Area. #31. Vocabulary. Volume is the number of cubic units needed to fill a space. V = lwh Ex:Volume is expressed in cubic units, so the volume of the prism is 5 cm · 2 cm · 3 cm = 30 cm 3. Example 1. Find the volume of the rectangular prism. Example 2.
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Vocabulary Volume is the number of cubic units needed to fill a space. V = lwh Ex:Volume is expressed in cubic units, so the volume of the prism is 5 cm · 2 cm · 3 cm = 30 cm3.
Example 1 Find the volume of the rectangular prism.
Example 2 Find the volume of each rectangular prism.
FYI To find the volume of any prism, you can use the formula V= Bh, where B is the area of the base, and h is the prism’s height.
Example 3 Find the volume of thetriangular prism.
Caution! The bases of a prism are always two congruent, parallel polygons. FYI
Vocabulary The surface area of a three-dimensional figure is the sum of the areas of its surfaces. To help you see all the surfaces of a three-dimensional figure, you can use a net. A net is the pattern made when the surface of a three-dimensional figure is layed out flat showing each face of the figure.
Example 1 • Find the surface area S of the prism. • Method 1: Use a net.
Example 2 • Find the surface area S of each prism. • Method 2: Use a three-dimensional drawing.
FYI The surface area of a pyramid equals the sum of the area of the base and the areas of the triangular faces. To find the surface area of a pyramid, think of its net.
Example 3 Find the surface area S of the pyramid.
Helpful Hint To find the area of the curved surface of a cylinder, multiply its height by the circumference of the base. FYI • The surface area of a cylinder equals the sum of the area of its bases and the area of its curved surface.
Example 4 Find the surface area S of the cylinder. Use 3.14 for , and round to the nearest hundredth.