Finding the Fourth Proportional to 1,123.18, 1,684.32 and 392.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.18 : 1,684.32 = 392.56 : x
2. Step 2: Convert to fraction form
   1,123.18/1,684.32 = 392.56/x
3. Step 3: Cross multiply
   1,123.18x = 1,684.32 × 392.56
4. Step 4: Simplify right side
   1,123.18x = 661,196.66
5. Step 5: Solve for x
   x = 661,196.66/1,123.18
6. Step 6: Final answer
   x = 588.68