Question

Two parallel lines are crossed by a transversal.

Horizontal and parallel lines k and l are cut by transversal j. At the intersection of lines k and j, the bottom left angle is 120 degrees. At the intersection of lines l and j, the top left angle is h degrees.
What is the value of h?

h = 60
h = 80
h = 100
h = 120

Answer 1

Answer: H = 60

Explanation: the parallel line (k) cut by the transversal line (j) forms two angles, one of size 120° and the other h°. These angles must be supplementary (add to 180°) therefore h = 180 -120 = 60°

Answer 2

∠h=60º

Explanation:

1) Since in a pair of parallel lines ∠α and ∠ h are Consecutive interior angles, their sum is 180º, i.e. they are supplementary angles. (Check the first graph)

`\alpha +h =180^(o)\Rightarrow 120^(0)+h =180^0\Rightarrow h=60^0`