Finding the Fourth Proportional to 11,142.50, 15,391.62 and 8,919.86

Step by Step Solution

1. Step 1: Write the proportion equation
   11,142.50 : 15,391.62 = 8,919.86 : x
2. Step 2: Convert to fraction form
   11,142.50/15,391.62 = 8,919.86/x
3. Step 3: Cross multiply
   11,142.50x = 15,391.62 × 8,919.86
4. Step 4: Simplify right side
   11,142.50x = 137,291,018.62
5. Step 5: Solve for x
   x = 137,291,018.62/11,142.50
6. Step 6: Final answer
   x = 12,321.39