Sine, Cosine and Tangent are the main functions used in Trigonometry and are based on a Right-Angled Triangle. Right-Angled Triangle A right-angled triangle (also called a right triangle) is a triangle with a right angle (90°) in it.A name to each side of a right triangle Sine, Cosine and Tangent Sine Example 1. - 30°, 150°- walking distance is 100m- Height : 1/2 * walking distance Example 2. ..