Finding the Fourth Proportional to 1,123.02, 1,685.30 and 392.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.02 : 1,685.30 = 392.60 : x
2. Step 2: Convert to fraction form
   1,123.02/1,685.30 = 392.60/x
3. Step 3: Cross multiply
   1,123.02x = 1,685.30 × 392.60
4. Step 4: Simplify right side
   1,123.02x = 661,648.78
5. Step 5: Solve for x
   x = 661,648.78/1,123.02
6. Step 6: Final answer
   x = 589.17