Finding the Fourth Proportional to 12,811.78, 17,680.27 and 7,146.89

Step by Step Solution

1. Step 1: Write the proportion equation
   12,811.78 : 17,680.27 = 7,146.89 : x
2. Step 2: Convert to fraction form
   12,811.78/17,680.27 = 7,146.89/x
3. Step 3: Cross multiply
   12,811.78x = 17,680.27 × 7,146.89
4. Step 4: Simplify right side
   12,811.78x = 126,358,944.86
5. Step 5: Solve for x
   x = 126,358,944.86/12,811.78
6. Step 6: Final answer
   x = 9,862.72