Finding the Fourth Proportional to 81,411.36, 121,906.72 and 56,188.72

Step by Step Solution

1. Step 1: Write the proportion equation
   81,411.36 : 121,906.72 = 56,188.72 : x
2. Step 2: Convert to fraction form
   81,411.36/121,906.72 = 56,188.72/x
3. Step 3: Cross multiply
   81,411.36x = 121,906.72 × 56,188.72
4. Step 4: Simplify right side
   81,411.36x = 6,849,782,556.20
5. Step 5: Solve for x
   x = 6,849,782,556.20/81,411.36
6. Step 6: Final answer
   x = 84,137.92