Finding the Fourth Proportional to 21,978.78, 30,330.72 and 11,907.29

Step by Step Solution

1. Step 1: Write the proportion equation
   21,978.78 : 30,330.72 = 11,907.29 : x
2. Step 2: Convert to fraction form
   21,978.78/30,330.72 = 11,907.29/x
3. Step 3: Cross multiply
   21,978.78x = 30,330.72 × 11,907.29
4. Step 4: Simplify right side
   21,978.78x = 361,156,584.17
5. Step 5: Solve for x
   x = 361,156,584.17/21,978.78
6. Step 6: Final answer
   x = 16,432.06