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Area of a circle

Excel formula: Area of a circle
Generic formula 
=PI()*A1^2
Summary 

To calculate the area of a circle, you can use the PI function together with the exponent operator (^). In the example shown, the formula in C5, copied down, is:

=PI()*B5^2

which calculates the area of a circle with the radius given in column B.

Explanation 

In geometry, the area enclosed by a circle with radius (r) is defined by the following formula: πr2

The Greek letter π ("pi") represents the ratio of the circumference of a circle to its diameter. In Excel, π is represented in a formula with the PI function, which returns the number 3.14159265358979, accurate to 15 digits:

=PI() // returns 3.14159265358979

To square a number in Excel, you can use the exponentiation operator (^):

=A1^2

Or, you can use the POWER function:

=POWER(A1,2)

Rewriting the formula =πr2 as an Excel formula to for the example, we get:

=PI()*B5^2

Or:

=PI()*POWER(B5,2)

The result is the same for both formulas. Following Excel's order of operations, exponentiation will occur before multiplication.

Author 
Dave Bruns

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