Finding the Fourth Proportional to 9,288.40, 12,817.72 and 6,139.12

Step by Step Solution

1. Step 1: Write the proportion equation
   9,288.40 : 12,817.72 = 6,139.12 : x
2. Step 2: Convert to fraction form
   9,288.40/12,817.72 = 6,139.12/x
3. Step 3: Cross multiply
   9,288.40x = 12,817.72 × 6,139.12
4. Step 4: Simplify right side
   9,288.40x = 78,689,521.21
5. Step 5: Solve for x
   x = 78,689,521.21/9,288.40
6. Step 6: Final answer
   x = 8,471.81