Finding the Fourth Proportional to 56,656.40, 78,139.56 and 39,654.80

Step by Step Solution

1. Step 1: Write the proportion equation
   56,656.40 : 78,139.56 = 39,654.80 : x
2. Step 2: Convert to fraction form
   56,656.40/78,139.56 = 39,654.80/x
3. Step 3: Cross multiply
   56,656.40x = 78,139.56 × 39,654.80
4. Step 4: Simplify right side
   56,656.40x = 3,098,608,623.89
5. Step 5: Solve for x
   x = 3,098,608,623.89/56,656.40
6. Step 6: Final answer
   x = 54,691.24