Finding the Fourth Proportional to 39,890.18, 55,046.30 and 21,981.62

Step by Step Solution

1. Step 1: Write the proportion equation
   39,890.18 : 55,046.30 = 21,981.62 : x
2. Step 2: Convert to fraction form
   39,890.18/55,046.30 = 21,981.62/x
3. Step 3: Cross multiply
   39,890.18x = 55,046.30 × 21,981.62
4. Step 4: Simplify right side
   39,890.18x = 1,210,006,849.01
5. Step 5: Solve for x
   x = 1,210,006,849.01/39,890.18
6. Step 6: Final answer
   x = 30,333.45