Finding the Fourth Proportional to 20,146.32, 30,217.86 and 12,729.15

Step by Step Solution

1. Step 1: Write the proportion equation
   20,146.32 : 30,217.86 = 12,729.15 : x
2. Step 2: Convert to fraction form
   20,146.32/30,217.86 = 12,729.15/x
3. Step 3: Cross multiply
   20,146.32x = 30,217.86 × 12,729.15
4. Step 4: Simplify right side
   20,146.32x = 384,647,672.62
5. Step 5: Solve for x
   x = 384,647,672.62/20,146.32
6. Step 6: Final answer
   x = 19,092.70