Finding the Fourth Proportional to 21,932.53, 30,265.05 and 12,978.47

Step by Step Solution

1. Step 1: Write the proportion equation
   21,932.53 : 30,265.05 = 12,978.47 : x
2. Step 2: Convert to fraction form
   21,932.53/30,265.05 = 12,978.47/x
3. Step 3: Cross multiply
   21,932.53x = 30,265.05 × 12,978.47
4. Step 4: Simplify right side
   21,932.53x = 392,794,043.47
5. Step 5: Solve for x
   x = 392,794,043.47/21,932.53
6. Step 6: Final answer
   x = 17,909.20