Finding the Fourth Proportional to 39,123.89, 53,990.99 and 21,218.83

Step by Step Solution

1. Step 1: Write the proportion equation
   39,123.89 : 53,990.99 = 21,218.83 : x
2. Step 2: Convert to fraction form
   39,123.89/53,990.99 = 21,218.83/x
3. Step 3: Cross multiply
   39,123.89x = 53,990.99 × 21,218.83
4. Step 4: Simplify right side
   39,123.89x = 1,145,625,476.84
5. Step 5: Solve for x
   x = 1,145,625,476.84/39,123.89
6. Step 6: Final answer
   x = 29,281.99