Write a program to determine how much grass a cow can eat. A cow is attached to a rope of length $c$, and the other end of the rope is attached to a corner of a rectangular house of width $a$ and depth $b$. Please determine the area the cow can browse.
The input has three double precision number $a$, $b$, and $c$.
The output has a double precision number (in
- We assume that $\pi = 3.1415926$.
- $0 \lt a, \; b \le 1000$
- $c \le a+b$
10.0 10.0 5.0