The horizontal lines are parallel. Draw the figure on a piece of paper. Now, extend the segment that forms the 36-deg angle with the upper horizontal line until it intersects the lower horizontal line. Now you have a triangle. One angle of the triangle is 31 degrees at the bottom right. At the bottom left, you have an angle that is an alternate interior angle to the 36-deg angle at the top right, so the angle at the bottom left of the triangle also measures 36 deg. Angle 1 is an exterior angle of this triangle. The measure of an exterior angle of a triangle is the sum of the measures of the remote interior angles. The 31-deg angle and the 36-deg angle are the remote interior angles to angle 1, so m<1 = 31 + 36 = 67.