Finding the Fourth Proportional to 86,411.16, 129,513.24 and 56,439.72

Step by Step Solution

1. Step 1: Write the proportion equation
   86,411.16 : 129,513.24 = 56,439.72 : x
2. Step 2: Convert to fraction form
   86,411.16/129,513.24 = 56,439.72/x
3. Step 3: Cross multiply
   86,411.16x = 129,513.24 × 56,439.72
4. Step 4: Simplify right side
   86,411.16x = 7,309,691,001.89
5. Step 5: Solve for x
   x = 7,309,691,001.89/86,411.16
6. Step 6: Final answer
   x = 84,591.98