anonymous one year ago the sum of the measure of the interior angle of a triangle is equal to_____. A. 90 B.180 C.270 D.360

So all 3 interior angles in a triangle add up to 180 >.< I don't actually know why, though >.< @Elsa213

2. Michele_Laino

hint: the sum S of internal angles of a polygon is given by the subsequent formula: $\Large S = \left( {n - 2} \right) \times 180$ where n is the number of sides of our polygon. In our case we have a triangle, so, n=3

3. Michele_Laino

then, after a substitution, we get: $\Large S = \left( {n - 2} \right) \times 180 = \left( {3 - 2} \right) \times 180 = ...?$

4. anonymous

90 is the answer