The factorial of the number 0 is defined as 1 because there is only one possible permutation for a set of zero elements, namely the empty set. The combinatorial interpretation of the factorial function is the total numbe... More »

There are 10,000 possible 4-digit combinations for a phone that dials 0 through 9 if repetition is allowed. Some of the combinations include {0,0,0,0}, {9,9,9,9} and all arrangements between. Since the order of digits ma... More »

The number sequence 127.0.0.1 refers to the Internet Protocol (IP) address used to designate a computer as a local host. Otherwise known as a "loopback" address, it bypasses local network hardware. 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 »

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 »

To divide a circle into eight equal pieces with three straight lines, first draw two diameters that partition the circle into four sections. Next, separate and rearrange the sections, and then use a third line to cut the... More »

Real-life examples of trapezoids include certain table tops, bridge supports, handbag sides and architectural elements. Since a trapezoid cannot be three-dimensional, many real-life examples of trapezoids are only partly... More »