Two parallel lines, e and f, are crossed by two transversals. Horizontal and parallel lines e and f are cut by transversals c and d. All angles are described clockwise, from uppercase left. At the intersection of lines e and c, the angles are: 1, 2, 4, 3. At the intersection of lines f and c, the angles are 5, 6, 8, 7. At the intersection of lines e and d, the angles are: 9, 97 degrees, 12, 11. At the intersection of lines f and d, the angles are 13, 14, 16, 15. What is the measure of Angle15? mAngle15 = 77° mAngle15 = 83° mAngle15 = 93° mAngle15 = 97°