Finding the Fourth Proportional to 31,905, 47,879.42 and 11,128.50

Step by Step Solution

1. Step 1: Write the proportion equation
   31,905 : 47,879.42 = 11,128.50 : x
2. Step 2: Convert to fraction form
   31,905/47,879.42 = 11,128.50/x
3. Step 3: Cross multiply
   31,905x = 47,879.42 × 11,128.50
4. Step 4: Simplify right side
   31,905x = 532,826,069.83
5. Step 5: Solve for x
   x = 532,826,069.83/31,905
6. Step 6: Final answer
   x = 16,700.39