Which correctly describes how to determine the measure of angle 1? 2 parallel lines are crossed by a transversal to form 8 angles. Clockwise from top left, the angles are 1, 2, blank, blank; blank 81 degrees, blank, blank. The 81° angle and angle 2 are corresponding angles so angle 2 must measure 81°. Angles 1 and 2 are supplementary angles so angle 1 must measure 99°. The 81° angle and angle 2 are alternate interior angles so angle 2 must measure 81°. Angles 1 and 2 are supplementary angles so angle 1 must measure 99°. The 81° angle and angle 2 are corresponding angles so angle 2 must measure 99°. Angles 1 and 2 are supplementary angles so angle 1 must measure 81°. The 81° angle and angle 2 are alternate interior angles so angle 2 must measure 99°. Angles 1 and 2 are supplementary angles so angle 1 must measure 81°.