Finding the Fourth Proportional to 13,881.20, 20,788.43 and 7,940.07

Step by Step Solution

1. Step 1: Write the proportion equation
   13,881.20 : 20,788.43 = 7,940.07 : x
2. Step 2: Convert to fraction form
   13,881.20/20,788.43 = 7,940.07/x
3. Step 3: Cross multiply
   13,881.20x = 20,788.43 × 7,940.07
4. Step 4: Simplify right side
   13,881.20x = 165,061,549.69
5. Step 5: Solve for x
   x = 165,061,549.69/13,881.20
6. Step 6: Final answer
   x = 11,891.02