Finding the Fourth Proportional to 1,123.32, 1,685.46 and 439.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.32 : 1,685.46 = 439.80 : x
2. Step 2: Convert to fraction form
   1,123.32/1,685.46 = 439.80/x
3. Step 3: Cross multiply
   1,123.32x = 1,685.46 × 439.80
4. Step 4: Simplify right side
   1,123.32x = 741,265.31
5. Step 5: Solve for x
   x = 741,265.31/1,123.32
6. Step 6: Final answer
   x = 659.89