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.

Find a in terms of b and c.
What can you say about the triangles if a=b=c?
Age 14 to 16
NRICH provides thousands of free online mathematics resources for ages 3 to 18, covering all stages of early years, primary and secondary school education – completely free and available to all.
Do you enjoy thought-provoking questions? If so, this is the place for you.
What are you looking for?
Organization
Website URL
Type of Resource
Assigned Categories
Resource k12
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.

Find a in terms of b and c.
What can you say about the triangles if a=b=c?
Age 14 to 16
NRICH provides thousands of free online mathematics resources for ages 3 to 18, covering all stages of early years, primary and secondary school education – completely free and available to all.
Do you enjoy thought-provoking questions? If so, this is the place for you.
