183k views
5 votes
Find missing angle
Please help man

Find missing angle Please help man-example-1
User Furqan Ali
by
5.0k points

1 Answer

3 votes

9514 1404 393

Answer:

angles 1-8 are 62°, 71°, 109°, 35°, 109°, 29°, 47°, 62°

Explanation:

It is convenient to make use of the relations ...

  • an exterior angle of a triangle is equal to the sum of the remote interior angles
  • vertical angles are congruent
  • a linear pair is supplementary
  • at a transversal of parallel lines, alternate interior angles are congruent
  • at a transversal of parallel lines, adjacent interior angles are supplementary

Using these relations, we have ...

∠2 = 71° (vertical angles)

∠3 = ∠5 = 180° -71° = 109°

∠1 +47° = ∠3 = 109° ⇒ ∠1 = ∠8 = 62° (alt int angles)

∠4 +36° = 71° ⇒ ∠4 = 35°

∠6 +42° = ∠2 = 71° ⇒ ∠6 = 29°

∠7 = 47° (alt int angles)

There are other ways to work these, using the sum of angles in a triangle, for example.

In order, angles 1-8 are ...

62°, 71°, 109°, 35°, 109°, 29°, 47°, 62°

User Ossie
by
4.1k points