sin 45° = cos 45° = ≈ 0.71
tan 45° = 1If we know the values of these functions for other acute angles, we can use them to
figure out the missing sides of a right triangle. This is one of the most common uses
of trig for the physics in this book. For example, consider the triangle below with
hypotenuse 5 and containing an acute angle, θ, of measure 30°: