Finding the Fourth Proportional to 13,139.31, 18,129.77 and 7,834.62

Step by Step Solution

1. Step 1: Write the proportion equation
   13,139.31 : 18,129.77 = 7,834.62 : x
2. Step 2: Convert to fraction form
   13,139.31/18,129.77 = 7,834.62/x
3. Step 3: Cross multiply
   13,139.31x = 18,129.77 × 7,834.62
4. Step 4: Simplify right side
   13,139.31x = 142,039,960.90
5. Step 5: Solve for x
   x = 142,039,960.90/13,139.31
6. Step 6: Final answer
   x = 10,810.30