Finding the Fourth Proportional to 2,147.47, 3,219.63 and 685.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,147.47 : 3,219.63 = 685.78 : x
2. Step 2: Convert to fraction form
   2,147.47/3,219.63 = 685.78/x
3. Step 3: Cross multiply
   2,147.47x = 3,219.63 × 685.78
4. Step 4: Simplify right side
   2,147.47x = 2,207,957.86
5. Step 5: Solve for x
   x = 2,207,957.86/2,147.47
6. Step 6: Final answer
   x = 1,028.17