Finding the Fourth Proportional to 1,128.93, 1,693.56 and 398.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.93 : 1,693.56 = 398.31 : x
2. Step 2: Convert to fraction form
   1,128.93/1,693.56 = 398.31/x
3. Step 3: Cross multiply
   1,128.93x = 1,693.56 × 398.31
4. Step 4: Simplify right side
   1,128.93x = 674,561.88
5. Step 5: Solve for x
   x = 674,561.88/1,128.93
6. Step 6: Final answer
   x = 597.52