## Basic College Mathematics (9th Edition)

It is not possible for a triangle to have two right angles. The measure of a right angle is 90$^{\circ}$. Therefore, two right angles would equal 180$^{\circ}$. Since the sum of all three angles in the triangle should equal 180$^{\circ}$ it makes this impossible since the sum would already be 180$^{\circ}$ before the addition of the third angle.