r=4.2

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=4.2 into the formula for the area of a circle. Pi π is approximately equal to 3.14.

π⋅4.22

Raise 4.2 to the power of 2.

π⋅17.64

Multiply π by 17.64.

55.4176944

Find the Area circle (4.2)