Finding the Fourth Proportional to 21,978.60, 30,330.43 and 11,907.30

Step by Step Solution

1. Step 1: Write the proportion equation
   21,978.60 : 30,330.43 = 11,907.30 : x
2. Step 2: Convert to fraction form
   21,978.60/30,330.43 = 11,907.30/x
3. Step 3: Cross multiply
   21,978.60x = 30,330.43 × 11,907.30
4. Step 4: Simplify right side
   21,978.60x = 361,153,347.72
5. Step 5: Solve for x
   x = 361,153,347.72/21,978.60
6. Step 6: Final answer
   x = 16,432.05