Finding the Fourth Proportional to 9,412.56, 12,989.16 and 5,220.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,412.56 : 12,989.16 = 5,220.72 : x
2. Step 2: Convert to fraction form
   9,412.56/12,989.16 = 5,220.72/x
3. Step 3: Cross multiply
   9,412.56x = 12,989.16 × 5,220.72
4. Step 4: Simplify right side
   9,412.56x = 67,812,767.40
5. Step 5: Solve for x
   x = 67,812,767.40/9,412.56
6. Step 6: Final answer
   x = 7,204.50