Finding the Fourth Proportional to 8,287.32, 12,443.25 and 8,139.69

Step by Step Solution

1. Step 1: Write the proportion equation
   8,287.32 : 12,443.25 = 8,139.69 : x
2. Step 2: Convert to fraction form
   8,287.32/12,443.25 = 8,139.69/x
3. Step 3: Cross multiply
   8,287.32x = 12,443.25 × 8,139.69
4. Step 4: Simplify right side
   8,287.32x = 101,284,197.59
5. Step 5: Solve for x
   x = 101,284,197.59/8,287.32
6. Step 6: Final answer
   x = 12,221.59