Question

Parallel lines r and s are cut by two transversals, parallel lines t and u.

Lines r and s are crossed by lines t and u to form 16 angles. Clockwise from top left, at the intersection of r and t, the angles are 1, 2, 3, 4; at the intersection of s and t, 5, 6, 7, 8; at the intersection of u and s, 9, 10, 11, 12; at the intersection of u and r, 13, 14, 15, 16.

Which angles are alternate exterior angles with angle 11?
Angle5 and Angle13
Angle7 and Angle15
Angle6 and Angle16
Angle8 and Angle14

Answer 1

Angle 5 and Angle 13.

Reason: Angle 11 (bottom-right at u∩s) and angle 13 (top-left at u∩r) are alternate exterior with respect to transversal u (and because t ∥ u, angle 5 is congruent to angle 13 as well).