Stage: 5 Challenge Level: 
A tetrahedron has two identical equilateral triangles faces, of side length 1 unit. The other two faces are right angled isosceles triangles. Find the exact volume of the tetrahedron.
Pythagoras' theorem. Tetrahedra. Manipulating algebraic expressions/formulae. alphas. Summation of series. Inequality/inequalities. Mathematical reasoning & proof. epsilons. Stage 5 - Reviewed 2012. Volume and capacity.
Published November 2001.
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