Finding the Fourth Proportional to 12,478.77, 17,220.56 and 7,173.18

Step by Step Solution

1. Step 1: Write the proportion equation
   12,478.77 : 17,220.56 = 7,173.18 : x
2. Step 2: Convert to fraction form
   12,478.77/17,220.56 = 7,173.18/x
3. Step 3: Cross multiply
   12,478.77x = 17,220.56 × 7,173.18
4. Step 4: Simplify right side
   12,478.77x = 123,526,140.71
5. Step 5: Solve for x
   x = 123,526,140.71/12,478.77
6. Step 6: Final answer
   x = 9,898.90