Question

Question 11 options:
m∥n, m∠1 = 65°, m∠2 = 60°, and m∠6 = 85°. What is m∠DBC?

Answer 1

∠DBC = 40°

Explanation:

∠5 = ∠3 + ∠4 = 180° - ∠6 . . . . relationship of angles at a transversal, vertical angles

∠3 = 180° - ∠1 - ∠2 . . . . . . sum of angles of a triangle

Then

∠4 = 180° - ∠6 - (180° - ∠1 - ∠2) = ∠1 +∠2 -∠6 . . . . substitute for ∠3

∠4 = 65° +60° -85° = 40°

∠4 = ∠DBC = 40°