Finding the Fourth Proportional to 9,139.56, 12,612.90 and 5,553.90

Step by Step Solution

1. Step 1: Write the proportion equation
   9,139.56 : 12,612.90 = 5,553.90 : x
2. Step 2: Convert to fraction form
   9,139.56/12,612.90 = 5,553.90/x
3. Step 3: Cross multiply
   9,139.56x = 12,612.90 × 5,553.90
4. Step 4: Simplify right side
   9,139.56x = 70,050,785.31
5. Step 5: Solve for x
   x = 70,050,785.31/9,139.56
6. Step 6: Final answer
   x = 7,664.57