Question

Question 8 options:

Below, l1∥l2, with transversal lines m and n.

Find the values of A and B.



A =

B =

Answer 1

• A = 105°
• B = 50°

Explanation:

Call the angle immediately CCW from B (below line l2) angle C. Then angle C is corresponding with the one marked 55°, so is 55°. Angle B+C is supplementary to the one marked 75°, so is 105° Then ...

angle B = (B+C) - C = 105°-55° = 50°

Angle A is an alternate exterior angle to angle (B+C), so is congruent to it. That means ...

angle A = angle (B+C) = 105°