# Sum of Interior Angles of a Polygon Proof

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Illustration used to prove “The sum of all the angles of any polygon is twice as many right angles as the polygon has sides, less four right angles.”

### Keywords

geometry, interior, proof, angle, angles, exterior, sum, theorem, polygonal angles, angles of a polygon### Galleries

Geometric Theorems and Proofs### Source

C.A. Hart, Daniel D. Feldman *Plane and Solid Geometry* (New York, NY: American Book Company, 1911)

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