For two right-angled triangles, if an angle (other than the right angle) is the same, the third angle will also be the same. This is true because angles in a triangle add up to 180°.

It has drawings and formula for the solution of right angled triangles, as well as tabulated values of openings required for plugs of differing sizes and different angles of opening. The pamphlet was ...

A 3,700-year old Babylonian clay tablet reveals an ancient method of constructing right-angled triangles that makes it the world’s oldest and most accurate trigonometric table.

For two right-angled triangles, if an angle (other than the right angle) is the same, the third angle will also be the same. This is true because angles in a triangle add up to 180°.