Finding the Fourth Proportional to 1,123.50, 1,685.25 and 439.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.50 : 1,685.25 = 439.50 : x
2. Step 2: Convert to fraction form
   1,123.50/1,685.25 = 439.50/x
3. Step 3: Cross multiply
   1,123.50x = 1,685.25 × 439.50
4. Step 4: Simplify right side
   1,123.50x = 740,667.38
5. Step 5: Solve for x
   x = 740,667.38/1,123.50
6. Step 6: Final answer
   x = 659.25