Question

Two parallel lines are crossed by a transversal.

Parallel lines x and y are cut by transversal w. On line x where it intersects with line w, 4 angles are created. Labeled clockwise, from uppercase left, the angles are: 2, 4, 3, 1. On line y where it intersects with line w, 4 angles are created. Labeled clockwise, from uppercase left, the angles are: 6, 8, 7, 5.
If mAngle6 = 123.5°, then mAngle1 is

56.5°.
67.5°.
123.5°.
136.5°.

Answer 1

56.5°.

Reason: angle 6 and angle 1 are same-side (consecutive) interior angles formed by a transversal of parallel lines, so they are supplementary. Thus angle1 = 180° − 123.5° = 56.5°.