Finding the Fourth Proportional to 818.31, 1,128.89 and 519.42

Step by Step Solution

1. Step 1: Write the proportion equation
   818.31 : 1,128.89 = 519.42 : x
2. Step 2: Convert to fraction form
   818.31/1,128.89 = 519.42/x
3. Step 3: Cross multiply
   818.31x = 1,128.89 × 519.42
4. Step 4: Simplify right side
   818.31x = 586,369.34
5. Step 5: Solve for x
   x = 586,369.34/818.31
6. Step 6: Final answer
   x = 716.56