Question

Draw a quadrilateral and mark the exterior angles at two vertices. Is there any relationship between the sum of these angles and the sum of the interior angles at the other two vertices?

Answer 1

Sum of the angles of the quadrilateral = 360°

Sum of the exterior angles = 360°

Let the sum of two exterior angles = x 

The sum of two interior angles at the same vertex = 360 – x. So the sum of the other two interior angles = x. So sum of two exterior angles at two vertices is equal to the sum of two interior angles at the other two vertices.