This self-contained book shows a unified and easy approach to trigonometry using triples like 3,4,5 which can represent the sides of a right-angled triangle.

This method is so powerful and simple that quite advanced topics can be tackled and understood at an earlier age than usual.

Though, as we see here, the usual sines, cosines etc. can be avoided they are included to connect up with the traditional approach.

This new edition includes 4 new chapters on the solution of right-angled triangles without use of a calculator.