Finding the Fourth Proportional to 64,989.57, 89,691.60 and 39,490.02

Step by Step Solution

1. Step 1: Write the proportion equation
   64,989.57 : 89,691.60 = 39,490.02 : x
2. Step 2: Convert to fraction form
   64,989.57/89,691.60 = 39,490.02/x
3. Step 3: Cross multiply
   64,989.57x = 89,691.60 × 39,490.02
4. Step 4: Simplify right side
   64,989.57x = 3,541,923,077.83
5. Step 5: Solve for x
   x = 3,541,923,077.83/64,989.57
6. Step 6: Final answer
   x = 54,499.87