Finding the Fourth Proportional to 22,418.56, 30,930.36 and 12,985.28

Step by Step Solution

1. Step 1: Write the proportion equation
   22,418.56 : 30,930.36 = 12,985.28 : x
2. Step 2: Convert to fraction form
   22,418.56/30,930.36 = 12,985.28/x
3. Step 3: Cross multiply
   22,418.56x = 30,930.36 × 12,985.28
4. Step 4: Simplify right side
   22,418.56x = 401,639,385.10
5. Step 5: Solve for x
   x = 401,639,385.10/22,418.56
6. Step 6: Final answer
   x = 17,915.49