The trigonometric functions (also called the circular functions) are functions of an angle. They relate the angles of a triangle to the lengths of its sides. The most familiar trigonometric functions are the sine, cosine, and tangent. To define the trigonometric functions for an angle , start with any right triangle that contains this angle . The three sides of the triangle are named: 1) hypotenuse (is the side opposite the right angle and always the longest side of the right-angled triangle).
2) opposite side (is the side opposite to the angle we are interested in)
3) adjacent side (Is the side having both the angles of interest )
The sine of an angle is defined as the ratio of the side opposite an angle of a right angled triangle to it’s hypotenuse.
|Length of opposite side (m)
|Length of hypotenuse (m)