if you continue the top ray down to the lower our the two lines you create an angle that it's an exterior angle of a triangle and it's also a corresponding angle to the 110° angle. since corresponding angles are congruent this angles is also 110°. this angle makes a linear pair with the angle to it left, the lower right angle on the triangle. linear pairs add to 180° so the angle has to be 70°. the lower left angle of this triangle is given as 37°. since the 3 angles of a triangle must add to 180° , the top angle has to be 180-(70+37)=73. since the top angle of the triangle makes a linear pair with the angle in question, our angle has to be 180-73=107°
