Answer:
The area would be,
Explanation:
Since, a very large or very small number can be written as the product of whole number and exponent ( a power ) of ten,
If a number is very large then we move the decimal to left side so that we get a whole number then the number of shifting is the power of ten,
While when we shift the decimal to the right side then the exponent of 10 is negative.
Here, the given number,
30,000 square miles,
The number of shifting to the left so that we get a whole number is 4,
By the above statement,
30,000 =

Hence, the estimated area of the lake would be
square miles