Finding the Fourth Proportional to 22,356, 30,851.28 and 12,420

Step by Step Solution

1. Step 1: Write the proportion equation
   22,356 : 30,851.28 = 12,420 : x
2. Step 2: Convert to fraction form
   22,356/30,851.28 = 12,420/x
3. Step 3: Cross multiply
   22,356x = 30,851.28 × 12,420
4. Step 4: Simplify right side
   22,356x = 383,172,897.60
5. Step 5: Solve for x
   x = 383,172,897.60/22,356
6. Step 6: Final answer
   x = 17,139.60