Finding the Fourth Proportional to 13,124.20, 18,111.42 and 7,155.91

Step by Step Solution

1. Step 1: Write the proportion equation
   13,124.20 : 18,111.42 = 7,155.91 : x
2. Step 2: Convert to fraction form
   13,124.20/18,111.42 = 7,155.91/x
3. Step 3: Cross multiply
   13,124.20x = 18,111.42 × 7,155.91
4. Step 4: Simplify right side
   13,124.20x = 129,603,691.49
5. Step 5: Solve for x
   x = 129,603,691.49/13,124.20
6. Step 6: Final answer
   x = 9,875.17