Finding the Fourth Proportional to 71,978.78, 99,326.21 and 39,713.78

Step by Step Solution

1. Step 1: Write the proportion equation
   71,978.78 : 99,326.21 = 39,713.78 : x
2. Step 2: Convert to fraction form
   71,978.78/99,326.21 = 39,713.78/x
3. Step 3: Cross multiply
   71,978.78x = 99,326.21 × 39,713.78
4. Step 4: Simplify right side
   71,978.78x = 3,944,619,252.17
5. Step 5: Solve for x
   x = 3,944,619,252.17/71,978.78
6. Step 6: Final answer
   x = 54,802.53