Finding the Fourth Proportional to 21,978.99, 30,330.77 and 11,907.18

Step by Step Solution

1. Step 1: Write the proportion equation
   21,978.99 : 30,330.77 = 11,907.18 : x
2. Step 2: Convert to fraction form
   21,978.99/30,330.77 = 11,907.18/x
3. Step 3: Cross multiply
   21,978.99x = 30,330.77 × 11,907.18
4. Step 4: Simplify right side
   21,978.99x = 361,153,878.39
5. Step 5: Solve for x
   x = 361,153,878.39/21,978.99
6. Step 6: Final answer
   x = 16,431.78