ISEE Upper Level Math : How to find an angle in an acute / obtuse isosceles triangle

Study concepts, example questions & explanations for ISEE Upper Level Math

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Example Questions

Example Question #1 : Isosceles Triangles

One of the base angles of an isosceles triangle is . Give the measure of the vertex angle.

Possible Answers:

Correct answer:


The base angles of an isosceles triangle are always equal. Therefore both base angles are .

Let the measure of the third angle. Since the sum of the angles of a triangle is , we can solve accordingly:

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