Finding the Fourth Proportional to 13,123.94, 18,111.21 and 7,155.71

Step by Step Solution

1. Step 1: Write the proportion equation
   13,123.94 : 18,111.21 = 7,155.71 : x
2. Step 2: Convert to fraction form
   13,123.94/18,111.21 = 7,155.71/x
3. Step 3: Cross multiply
   13,123.94x = 18,111.21 × 7,155.71
4. Step 4: Simplify right side
   13,123.94x = 129,598,475.95
5. Step 5: Solve for x
   x = 129,598,475.95/13,123.94
6. Step 6: Final answer
   x = 9,874.97