Finding the Fourth Proportional to 39,310.72, 54,248.76 and 21,405.72

Step by Step Solution

1. Step 1: Write the proportion equation
   39,310.72 : 54,248.76 = 21,405.72 : x
2. Step 2: Convert to fraction form
   39,310.72/54,248.76 = 21,405.72/x
3. Step 3: Cross multiply
   39,310.72x = 54,248.76 × 21,405.72
4. Step 4: Simplify right side
   39,310.72x = 1,161,233,766.91
5. Step 5: Solve for x
   x = 1,161,233,766.91/39,310.72
6. Step 6: Final answer
   x = 29,539.88