Finding the Fourth Proportional to 1,014.78, 1,521.50 and 398.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,014.78 : 1,521.50 = 398.55 : x
2. Step 2: Convert to fraction form
   1,014.78/1,521.50 = 398.55/x
3. Step 3: Cross multiply
   1,014.78x = 1,521.50 × 398.55
4. Step 4: Simplify right side
   1,014.78x = 606,391.83
5. Step 5: Solve for x
   x = 606,391.83/1,014.78
6. Step 6: Final answer
   x = 597.56