Finding the Fourth Proportional to 8,320.59, 11,422.31 and 7,139.61

Step by Step Solution

1. Step 1: Write the proportion equation
   8,320.59 : 11,422.31 = 7,139.61 : x
2. Step 2: Convert to fraction form
   8,320.59/11,422.31 = 7,139.61/x
3. Step 3: Cross multiply
   8,320.59x = 11,422.31 × 7,139.61
4. Step 4: Simplify right side
   8,320.59x = 81,550,803.00
5. Step 5: Solve for x
   x = 81,550,803.00/8,320.59
6. Step 6: Final answer
   x = 9,801.08