Finding the Fourth Proportional to 12,478.48, 17,221.20 and 7,174.72

Step by Step Solution

1. Step 1: Write the proportion equation
   12,478.48 : 17,221.20 = 7,174.72 : x
2. Step 2: Convert to fraction form
   12,478.48/17,221.20 = 7,174.72/x
3. Step 3: Cross multiply
   12,478.48x = 17,221.20 × 7,174.72
4. Step 4: Simplify right side
   12,478.48x = 123,557,288.06
5. Step 5: Solve for x
   x = 123,557,288.06/12,478.48
6. Step 6: Final answer
   x = 9,901.63