To find the area of the base of a square-based pyramid, we can use the formula for the volume of a pyramid:
\[ V = \frac{1}{3} \times \text{Base Area} \times \text{Height} \]
Given:
- Volume \( V = 66 \) cubic units
- Height \( h = 10 \) units
We can rearrange the formula to solve for the base area (\( A \)):
\[ A = \frac{3V}{h} \]
Substituting the given values:
\[ A = \frac{3 \times 66}{10} = \frac{198}{10} = 19.8 \text{ square units} \]
So, the area of the pyramid's base is 19.8 square units.