SOLUTION: A pennant for the sports teams at Lincoln High School is the shape of an isosceles triangle. If the measure of the vertex angle is 18, find the measure of each base angle.

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Question 180232: A pennant for the sports teams at Lincoln High School is the shape of an isosceles triangle. If the measure of the vertex angle is 18, find the measure of each base angle.
Answer by eperette(173) About Me  (Show Source):
You can put this solution on YOUR website!
Concepts you should now:
(1) The sum of the three interior angles of a triangle is 180
(2) An isosceles triangle has two sides that measure the same length (called legs) opposite two congruent angles (called based angles)
Therefore
2x + 18 = 180 , where x represents each base angle
2x+18-18=180-18
2x=162
2x/2=162/2
x=81
each base angle measure 81 degrees