Finding the Fourth Proportional to 21,989.52, 30,337.98 and 12,428.28

Step by Step Solution

1. Step 1: Write the proportion equation
   21,989.52 : 30,337.98 = 12,428.28 : x
2. Step 2: Convert to fraction form
   21,989.52/30,337.98 = 12,428.28/x
3. Step 3: Cross multiply
   21,989.52x = 30,337.98 × 12,428.28
4. Step 4: Simplify right side
   21,989.52x = 377,048,910.07
5. Step 5: Solve for x
   x = 377,048,910.07/21,989.52
6. Step 6: Final answer
   x = 17,146.75