Finding the Fourth Proportional to 12,443.12, 17,170.84 and 7,139.60

Step by Step Solution

1. Step 1: Write the proportion equation
   12,443.12 : 17,170.84 = 7,139.60 : x
2. Step 2: Convert to fraction form
   12,443.12/17,170.84 = 7,139.60/x
3. Step 3: Cross multiply
   12,443.12x = 17,170.84 × 7,139.60
4. Step 4: Simplify right side
   12,443.12x = 122,592,929.26
5. Step 5: Solve for x
   x = 122,592,929.26/12,443.12
6. Step 6: Final answer
   x = 9,852.27