NRICH: Terminology

Given an equilateral triangle inside an isosceles triangle, can you find a relationship between the angles?

The green triangle is an isosceles triangle while the blue triangle is an equilateral triangle.

An isoceles triangle circumscribing and equilateral triangle with angles between the vertices of the equilateral triangle and isosceles triangle of a, b and c
Find a in terms of b and c.

What can you say about the triangles if a=b=c?

Age 14 to 16

Math Topics
Algebra & Pre-Algebra, Equations, Geometry
High School, Educator
9th Grade, 10th Grade, 11th Grade

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NRICH (University of Cambridge)

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