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Overview
Grade 7 Math
Shape and Space
12. Develop and apply a formula for determining the area of triangles, parallelograms, circles
12.6 Polygons
Polygons: Sum of Interior and Exterior Angles
Understand what makes a shape a polygon, then master the formulas for the sum of interior angles and the sum of exterior angles of any polygon.
What You'll Learn
Identify a polygon by its straight sides, closed shape, and vertices, and classify it as convex or concave.
Distinguish regular polygons, which have equal sides and equal angles, from irregular polygons.
Apply the formula (n minus 2) times 180 degrees to find the sum of interior angles of any polygon.
Calculate each interior angle of a regular polygon by dividing the interior angle sum by the number of sides.
Recognize that the sum of exterior angles of any convex polygon always equals 360 degrees.
Use the exterior angle formula, 360 degrees divided by n, to find one exterior angle of a regular polygon.
This Unit Includes
Learning resources
PEI Curriculum Aligned