Finding the Fourth Proportional to 12,385.78, 17,106.57 and 8,155.75

Step by Step Solution

1. Step 1: Write the proportion equation
   12,385.78 : 17,106.57 = 8,155.75 : x
2. Step 2: Convert to fraction form
   12,385.78/17,106.57 = 8,155.75/x
3. Step 3: Cross multiply
   12,385.78x = 17,106.57 × 8,155.75
4. Step 4: Simplify right side
   12,385.78x = 139,516,802.85
5. Step 5: Solve for x
   x = 139,516,802.85/12,385.78
6. Step 6: Final answer
   x = 11,264.28