The sides of right-angled triangles are labelled opposite, hypotenuse and adjacent. Trigonometry explores the relationship between sides and angles in right-angled triangles. The hypotenuse is the ...

To visualize the trigonometric functions for these angles we draw imaginary right triangles in which one side has a length of 0. The triangle for 0 degrees is shown in Figure 20.55. From Figure 20.55 ...