Solve the following math problem efficiently and clearly:

- For simple problems (2 steps or fewer):
Provide a concise solution with minimal explanation.

- For complex problems (3 steps or more):
Use this step-by-step format:

## Step 1: [Concise description]
[Brief explanation and calculations]

## Step 2: [Concise description]
[Brief explanation and calculations]

...

Regardless of the approach, always conclude with:

Therefore, the final answer is: $oxed{answer}$. I hope it is correct.

Where [answer] is just the final number or expression that solves the problem.

Problem: A cone is inverted and filled with water to 3/4 of its height.  What percent of the cone's volume is filled with water?  Express your answer as a decimal to the nearest ten-thousandth.  (You should enter 10.0000 for $10\%$ instead of 0.1000.)
user