Prove the following theorem indirectly. we will give you a start.
prove that a triangle cannot have two right angles.
a triangle cannot have two right angles. suppose a triangle had two right angles.

A triangle cannot have two right angles because the sum of all three angles of a triangle is 180. If there were two right angles in a triangle, then the two angles themselves would equal to 180 degrees, without adding the third angles. Since the degrees added up would have to equal 180 and with two right angles it would be more than 180, there cannot be two right angles in a triangle.