Finding the Fourth Proportional to 10,120.86, 13,951.54 and 7,878.78

Step by Step Solution

1. Step 1: Write the proportion equation
   10,120.86 : 13,951.54 = 7,878.78 : x
2. Step 2: Convert to fraction form
   10,120.86/13,951.54 = 7,878.78/x
3. Step 3: Cross multiply
   10,120.86x = 13,951.54 × 7,878.78
4. Step 4: Simplify right side
   10,120.86x = 109,921,114.32
5. Step 5: Solve for x
   x = 109,921,114.32/10,120.86
6. Step 6: Final answer
   x = 10,860.85