Finding the Fourth Proportional to 9,399.56, 12,971.28 and 5,207.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,399.56 : 12,971.28 = 5,207.72 : x
2. Step 2: Convert to fraction form
   9,399.56/12,971.28 = 5,207.72/x
3. Step 3: Cross multiply
   9,399.56x = 12,971.28 × 5,207.72
4. Step 4: Simplify right side
   9,399.56x = 67,550,794.28
5. Step 5: Solve for x
   x = 67,550,794.28/9,399.56
6. Step 6: Final answer
   x = 7,186.59