Curriculum materials for students, schools and colleges created by MathsNet in partnership with AngliaCampus.

A B C D E F G H I J

Further info Tech

H1. Triangles and trig : right-angled triangles. A triangle which contains one angle measuring 90 degrees, or a right-angle, is called a right-angled triangle. This angle is usually marked with a square to indicate it is 90 degrees. In trigonometry it is important first to name correctly the sides of any right-angled triangle. The longest side (the one opposite the right angle) is always called the hypotenuse. Before naming the other sides, you must choose one of the remaining angles. This angle is normally refered to by the letter q, pronounced "theta". The side opposite this angle is called the opposite side, and the side next to, or adjacent to, this angle is called the adjacent side.   Sorry, this page requires a Java-compatible web browser. Drag any of the points A, B or C. The triangle remains right-angled.