Finding the Fourth Proportional to 39,887.89, 55,042.82 and 21,981.90

Step by Step Solution

1. Step 1: Write the proportion equation
   39,887.89 : 55,042.82 = 21,981.90 : x
2. Step 2: Convert to fraction form
   39,887.89/55,042.82 = 21,981.90/x
3. Step 3: Cross multiply
   39,887.89x = 55,042.82 × 21,981.90
4. Step 4: Simplify right side
   39,887.89x = 1,209,945,379.83
5. Step 5: Solve for x
   x = 1,209,945,379.83/39,887.89
6. Step 6: Final answer
   x = 30,333.65