# Question #9a19f

$\pi$, which is roughly equal to 3.14159265... is the ratio of a circle's circumference to its diameter. No matter how big or small the circle is, if it's a perfect circle its circumference will always be $\pi$ times its diameter.
$\pi$ was not a concept that was "invented" or "proposed", but rather it was discovered. It is guessed that $\pi$ was discovered by Egyptians or Babylonians some 3,000-4,000 years ago, however most values of $\pi$ back then were only approximations such as $\frac{25}{8}$, or the most well-known approximation $\frac{22}{7}$. Neither of these approximations are good enough for use in any application of modern mathematics.
${\pi}^{c}$ is simply $\pi$ raised to the power $c$, whatever $c$ happens to be. So if $c = 3$ then ${\pi}^{c} = {\pi}^{3} = \pi \cdot \pi \cdot \pi$.