Given the radius of a circle, calculate and print its area.
The area of a circle can be computed using the following formula:
For pi, you can use 3.141592653589793, or acos(-1)
.
The input will contain one floating-point number $r$ ($0 < r < 2000$).
Print the area of the circle (accurate to $10^{-4}$).
Input | Output |
---|---|
2 | 12.5663706144 |