Finding the Fourth Proportional to 10,913.86, 15,057.18 and 7,139.19

Step by Step Solution

1. Step 1: Write the proportion equation
   10,913.86 : 15,057.18 = 7,139.19 : x
2. Step 2: Convert to fraction form
   10,913.86/15,057.18 = 7,139.19/x
3. Step 3: Cross multiply
   10,913.86x = 15,057.18 × 7,139.19
4. Step 4: Simplify right side
   10,913.86x = 107,496,068.88
5. Step 5: Solve for x
   x = 107,496,068.88/10,913.86
6. Step 6: Final answer
   x = 9,849.50