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Area of Regular Polygons and Irregular Shapes. Lesson 7.3B
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Area of Regular Polygons and Irregular Shapes Lesson 7.3B M.3.G.2 Apply, using appropriate units, appropriate formulas (area, perimeter, surface area, volume) to solve application problems involving polygons, prisms, pyramids, cones, cylinders, spheres as well as composite figures, expressing solutions in both exact and approximate forms
Vocabulary • Apothem: • A line segment from the center of a polygon that is perpendicular to one of its sides Perimeter: The distance around a polygon Radius of a polygon: A line segment drawn from the center of a polygon to the vertex
Area of a Regular Polygon • Formula for finding the area of a regular polygon: A = ½ ap • Formula for finding the area of a regular triangle: • A =
Example • Find the area of the • regular polygon. Leave • your answer in simplest • radical form. 6 inches
Now You Try… • Find the area of the • regular polygon. Leave • your answer in simplest • radical form. 8 feet
Example • Find the area of the • regular polygon. Leave • your answer in simplest • radical form. 10 meters
Now You Try… • Find the area of the • regular polygon. Leave • your answer in simplest • radical form. 15 cm
Example • Find the area of the • regular polygon. Leave • your answer in simplest • radical form. 18 in
Now You Try… • Find the area of the • regular polygon. Leave • your answer in simplest • radical form. 4 in
Example • Find the area of the • regular polygon. Round • Your answer to • Nearest 10th. 5 mm
Now You Try… • Find the area of the • regular polygon. Round • Your answer to • Nearest 10th. 3 feet
Area of Irregular Shapes • Key to finding the area of irregular shapes: • Divide it into shapes you know!
20 cm 12 cm 4 cm 6 cm Example • Find the area of the given shape.
6" 15" 9" 8" Example • Find the area of the given shape.
12' 4' 12' 6' Now You Try… • Find the area of the given shape.