Finding the Fourth Proportional to 12,885.78, 19,336.88 and 12,780.32

Step by Step Solution

1. Step 1: Write the proportion equation
   12,885.78 : 19,336.88 = 12,780.32 : x
2. Step 2: Convert to fraction form
   12,885.78/19,336.88 = 12,780.32/x
3. Step 3: Cross multiply
   12,885.78x = 19,336.88 × 12,780.32
4. Step 4: Simplify right side
   12,885.78x = 247,131,449.47
5. Step 5: Solve for x
   x = 247,131,449.47/12,885.78
6. Step 6: Final answer
   x = 19,178.62