Very cool! Right, there are four different types of triangle. First, here's an isosceles triangle, it has two equal length sides and two equal angles. Oh! Very clever! Now we have an equilateral ...

The first four proofs presented in the paper have a notable limitation: they don’t work for isosceles right triangles ...

Very cool! Right, there are four different types of triangle. First, here's an isosceles triangle, it has two equal length sides and two equal angles. Oh! Very clever! Now we have an equilateral ...