Fill in the missing number.

To find the missing number, we can use algebra.

Let x be the missing number.

The equation is:

0.8x = 40,000

To solve for x, we divide both sides of the equation by 0.8:

x = 40,000 / 0.8

x = 50,000

Therefore, 80% of 50,000 is equal to 40,000.