This is a very important group

To better understand certain problems involving aircraft and propulsion it is necessary to use some mathematical ideas from trigonometry the study of triangles. Let us begin with some definitions and terminology which we will use on this slide. We start with a right triangle. A right triangle is a three sided figure with one angle equal to 90 degrees. A 90 degree angle is called a right angle and that is where the right triangle gets its name. We define the side of the triangle opposite from the right angle to be the hypotenuse, h. It is the longest side of the three sides of the right triangle. The word "hypotenuse" comes from two Greek words meaning "to stretch", since this is the longest side. We are going to label the other two sides a and b. The Pythagorean Theorem is a statement relating the lengths of the sides of any right triangle.

For any right triangle, the square of the hypotenuse
is equal to the sum of the squares of the other two sides.