What It Does
This formula will calculate the area of a circle given its radius.
How It Works
The area of a circle is given by Pi*Radius^2 where Pi is a constant approximately equal to 3.14159265. Excel has this constant built in as a function with no parameter inputs PI().
The POWER function will take any number and raise it to the power of any other number. POWER(Radius,2) will return the square of the Radius. In our example, POWER(3,2) results in 9, and 3.14159265*9 = 28.27.