Likewise, what is the sum of the angle measures in this shape?
The General RuleShapeSidesSum of Interior AnglesTriangle3180°Quadrilateral4360°Pentagon5540°Hexagon6720°
What is the measure of an interior angle in a regular quadrilateral?
What do the interior angles of a quadrilateral add up to?
This quadrilateral has been divided into two triangles, so the interior angles add up to 2 × 180 = 360°. This pentagon has been divided into three triangles, so the interior angles add up to 3 × 180 = 540°. In the same way, a hexagon can be divided into 4 triangles, a 7-sided polygon into 5 triangles etc.