Friday math movie: A clever way to estimate enormous numbers

To enter math, you can can either:

1. Use simple calculator-like input in the following format (surround your math in backticks, or qq on tablet or phone):
   `a^2 = sqrt(b^2 + c^2)`
   (See more on ASCIIMath syntax); or
2. Use simple LaTeX in the following format. Surround your math with \( and \).
   \( \int g dx = \sqrt{\frac{a}{b}} \)
   (This is standard simple LaTeX.)

NOTE: You can mix both types of math entry in your comment.