8.GR.A.3: Use informal arguments to verify that the sum of the interior angles of a triangle is 180 degrees and why an exterior angle equals the sum of the two remote interior angles.

Use informal arguments to verify that the sum of the interior angles of a triangle is 180 degrees and why an exterior angle equals the sum of the two remote interior angles.

Example Problems

Could

9, 33, \\text{ and } 31

be the side lengths of a triangle?

Could 8, 46, and 42 be the side lengths of a triangle?

Could 4, 47, and 43 be the side lengths of a triangle?

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