Every stop sign in America is an octagon, and every one of its eight corners measures exactly 135 degrees — no sign painter measures that; geometry guarantees it. In plain words, any polygon splits into triangles from one corner, giving n−2 triangles, and each triangle holds 180 degrees: sum = (n − 2) × 180°. A hexagon holds 720 degrees total; a regular one divides that evenly into six 120-degree corners. The Pentagon building's five sides work the same way, and so does every tiled floor pattern. Architects laying out bay windows, quilters piecing hexagonal blocks, and students finishing geometry worksheets all lean on this formula. It turns a protractor chore into one multiplication.

This calculator evaluates the interior-angle formulas. Type the number of sides n into the Variable A box, say 8 — Variable B accepts a second value for comparison. Read the angle sum from the Result box: (8−2) × 180 = 1080 degrees. Divide by 8 yourself to confirm each corner of a regular octagon is 135 degrees, and try n = 5 to see the Pentagon's 540-degree total.

With the pre-filled defaults — Variable A 10, Variable B 5 — the Interior Angles Of Polygon Calculator returns Result 50.0000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.