Question

Prove that angles of rectangle are right angles

Answer 1

in a rectangle the diagonals divide it in to two congruent triangles . this shows that all the angles are equal which implies that sum of all angles is 360.which shows that all angles are of 90.

Answer 2

A rectangle is DEFINED to be a four sided polygon with all angles congruent.

The angle sum of a polygon of "n" sides is . So for a quadrilateral, the angle sum is .

Since all the angles are equal, that means if "a" is one of the angles, then .

Therefore, the angles in a rectangle are all right angles.