Finding the Fourth Proportional to 9,414.90, 12,987.69 and 6,388.98

Step by Step Solution

1. Step 1: Write the proportion equation
   9,414.90 : 12,987.69 = 6,388.98 : x
2. Step 2: Convert to fraction form
   9,414.90/12,987.69 = 6,388.98/x
3. Step 3: Cross multiply
   9,414.90x = 12,987.69 × 6,388.98
4. Step 4: Simplify right side
   9,414.90x = 82,978,091.66
5. Step 5: Solve for x
   x = 82,978,091.66/9,414.90
6. Step 6: Final answer
   x = 8,813.49