What is the sum of the interior angles of a 8-sided polygon?

1080

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Well, here's how you can solve that: A triangle's interior has a measurement of 180. A square (and all quadrilaterals, which means a shape with four sides) has a measurement of 360. A pentagon has a measurement of 540. A heptagon has a measurement of 720. All you do to get the total angle measurement of more sided shapes (and in your case polygons) that go up from heptagon as well as below it, all you do is add to get the measurement of a larger interior, or subtract for a smaller interior.