The triangle angle sum theorem tells us that, given a triangle in flat Euclidean geometry, the sum of the measures of the interior angles is 180 degrees. But our problem doesn’t give us a triangle.

The sum of interior angles in a triangle is 180˚. In an equilateral triangle, all three angles are equal to 60˚. To find the missing angles in an equilateral triangle, ...

The angle sum of a triangle is 180 degrees. That means all triangles, no matter how differently formed, will have angles that add up to 180 degrees. These angles all add up to equal 180 degrees.

We need five angles, each of which can combine with copies of itself and the others to sum to 360. But we also need five sides that will fit together with those angles. Further complicating matters, a ...

What it means is that in a right triangle (where one angle equals 90°), the sum of the squares of two sides equals the square of the hypotenuse (the longest side). Or, to put it another way: ...