volume_mute

Refer to the below figure

publish date2024/03/01 01:47:00 UTC

volume_mute

If \(l_1 \parallel l_2 \) and m(∠3) = 120o, find the measures of the other seven angles that are labelled.

  1. m(∠1) =
  2. m(∠2) =
  3. m(∠4) =
  4. m(∠5) =
  5. m(∠6) =
  6. m(∠7) =
  7. m(∠8) =

Correct Answer

(1) 60
(2) 120
(3) 60
(4) 60
(5) 120
(6) 120
(7) 60

Explanation

  1. m(∠1) = 60o
    • ∠3 and ∠1 are supplementary: m(∠3) + m(∠1) = 180o
  2. m(∠2) = 120o
    • Vertical angles are congruent: m(∠2) = m(∠3)
  3. m(∠4) = 60o
    • Vertical angles are congruent: m(∠4) = m(∠1)
  4. m(∠5) = 60o
    • If two parallel lines are cut by a transversal, alternate interior angles are congruent: m(∠5) = m(∠4).
  5. m(∠6) = 120o
    • If two parallel lines are cut by a transversal, alternate interior angles are congruent: m(∠6) = m(∠3).
  6. m(∠7) = 120o
    • Vertical angles are congruent: m(∠7) = m(∠6)
  7. m(∠8) = 60o
    • Vertical angles are congruent: m(∠8) = m(∠5)

Reference

Mathematics for college students