Triangle QRS is a right triangle with the right angle at vertex R. The sum of m∠Q and m∠S must be equal to 45°. greater than 45° and less than 90°. equal to 90°. greater than 90° and less than 180°.
According to the triangle sum theorem, all the angles in a triangle must add up to 180 degrees. If we know one angle is already 90, we do 180-90=90. The other 2 angles must add up to 90, exactly.
