r=10.4

The area of a circle is equal to Pi π times the radius r squared.

π⋅(radius)2

Substitute in the value of the radius r=10.4 into the formula for the area of a circle. Pi π is approximately equal to 3.14.

π⋅10.42

Raise 10.4 to the power of 2.

π⋅108.16

Multiply π by 108.16.

339.79466141

Find the Area circle (10.4)