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

Algebra & Pre-Algebra, Equations, Geometry
High School, Educator

What are you looking for?


NRICH (University of Cambridge)

Website URL

Type of Resource


Assigned Categories