Finding the Fourth Proportional to 825.89, 1,139.31 and 494.24

Step by Step Solution

1. Step 1: Write the proportion equation
   825.89 : 1,139.31 = 494.24 : x
2. Step 2: Convert to fraction form
   825.89/1,139.31 = 494.24/x
3. Step 3: Cross multiply
   825.89x = 1,139.31 × 494.24
4. Step 4: Simplify right side
   825.89x = 563,086.88
5. Step 5: Solve for x
   x = 563,086.88/825.89
6. Step 6: Final answer
   x = 681.80