Finding the Fourth Proportional to 12,478.20, 17,220.34 and 7,174.12

Step by Step Solution

1. Step 1: Write the proportion equation
   12,478.20 : 17,220.34 = 7,174.12 : x
2. Step 2: Convert to fraction form
   12,478.20/17,220.34 = 7,174.12/x
3. Step 3: Cross multiply
   12,478.20x = 17,220.34 × 7,174.12
4. Step 4: Simplify right side
   12,478.20x = 123,540,785.60
5. Step 5: Solve for x
   x = 123,540,785.60/12,478.20
6. Step 6: Final answer
   x = 9,900.53