Chapter Closure
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Isosceles Triangle Theorem |
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If two sides in a triangle are congruent, then the angles opposite them are congruent. |
LHS-4x=RHS-4x
LHS-5^(∘)=RHS-5^(∘)
Rearrange equation
Two lines are intersected by a transversal. Notice that we do not know whether those two lines are parallel or not. Since no other information is given, we cannot determine the value of y.
We can use the Triangle Exterior Angle Theorem, which states that the measure of an exterior angle of a triangle is equal to the sum of its two remote interior angles.
Let's use this theorem to write and solve an equation for the missing variable. 40^(∘) + z = 117^(∘) ⇔ z = 77^(∘)