Finding the Fourth Proportional to 1,123.16, 1,684.71 and 392.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.16 : 1,684.71 = 392.72 : x
2. Step 2: Convert to fraction form
   1,123.16/1,684.71 = 392.72/x
3. Step 3: Cross multiply
   1,123.16x = 1,684.71 × 392.72
4. Step 4: Simplify right side
   1,123.16x = 661,610.89
5. Step 5: Solve for x
   x = 661,610.89/1,123.16
6. Step 6: Final answer
   x = 589.06