Finding the Fourth Proportional to 12,856.76, 19,284.78 and 4,092.20

Step by Step Solution

1. Step 1: Write the proportion equation
   12,856.76 : 19,284.78 = 4,092.20 : x
2. Step 2: Convert to fraction form
   12,856.76/19,284.78 = 4,092.20/x
3. Step 3: Cross multiply
   12,856.76x = 19,284.78 × 4,092.20
4. Step 4: Simplify right side
   12,856.76x = 78,917,176.72
5. Step 5: Solve for x
   x = 78,917,176.72/12,856.76
6. Step 6: Final answer
   x = 6,138.19