The number Pi, symbolized by a Greek letter, has a constant value that approximately equals 3.14159. Pi is an irrational number, which means it cannot be expressed as a common fraction, and it has an infinite decimal rep... More »

Cos(2pi) is equal to 1. The cosine function, cos(x), oscillates between 1 and -1 with a period of 2pi as x varies. By definition, cos(0) = 1, and the periodicity of the function means the cosine of all multiples of 2pi (... More »

The concept of the mathematical constant pi dates back approximately 4000 years to ancient Mesopotamia. Babylonian mathematicians found that the area of a circle was figured by taking the square of the radius, multiplied... More »

The mathematical constant pi has many uses, most of which are associated with the circle or circular objects. Often, pi is used for geometric purposes, such as calculating the area of a circle or the volume of a sphere. More »

The formula for the area of any triangle equals 1/2 the base times the height. For a right triangle, this is easy to remember ,since a right triangle is half of a rectangle on one side of its diagonal, and the area of a ... More »

To find out what a tangent equals, use the equation for a tangent, which is tan(degrees) = opposite / adjacent. This equation will determine what the tangent of an angle equals by using the triangle's opposite angle and ... More »

Euclid was a Greek mathematician who is famous for writing a series of 13 books called Elements about geometry and other mathematical concepts. His concepts and explanations of plane geometry, which take up approximately... More »