Finding the Fourth Proportional to 12,399.72, 17,109.54 and 7,431.72

Step by Step Solution

1. Step 1: Write the proportion equation
   12,399.72 : 17,109.54 = 7,431.72 : x
2. Step 2: Convert to fraction form
   12,399.72/17,109.54 = 7,431.72/x
3. Step 3: Cross multiply
   12,399.72x = 17,109.54 × 7,431.72
4. Step 4: Simplify right side
   12,399.72x = 127,153,310.61
5. Step 5: Solve for x
   x = 127,153,310.61/12,399.72
6. Step 6: Final answer
   x = 10,254.53