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Alternate Exterior Angles - Concept 11,729 views

Teacher/Instructor Brian McCall
Brian McCall

Univ. of Wisconsin
J.D. Univ. of Wisconsin Law school

Brian was a geometry teacher through the Teach for America program and started the geometry program at his school

Alternate exterior angles are formed by a transversal intersecting two parallel lines . They are located "outside" the two parallel lines but on opposite sides of the transversal, creating two pairs (four total angles) of alternate exterior angles. Alternate exterior angles are congruent, meaning they have equal measure.

If we have two parallel lines and again I know parallel lines because they have the same number of arrows. And they're intersected by a transversal, then these angles on the outside that are on opposite sides of this transversal will also be congruent.
So angles one and seven are on opposite sides of the transversal and they're on the exterior part of the of the parallel lines. So if we're going to say, is if you have two parallel lines intersected by a transversal then alternate exterior angles are congruent. So alternate, exterior angles are congruent, so one and seven are going to be congruent and angle eight and two which is on the opposite side are also going to be congruent.
So alternate meaning on different sides of the transversal exterior meaning on the outer part of the parallel lines.

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