Finding the Fourth Proportional to 1,056.78, 1,585.18 and 440.33

Step by Step Solution

1. Step 1: Write the proportion equation
   1,056.78 : 1,585.18 = 440.33 : x
2. Step 2: Convert to fraction form
   1,056.78/1,585.18 = 440.33/x
3. Step 3: Cross multiply
   1,056.78x = 1,585.18 × 440.33
4. Step 4: Simplify right side
   1,056.78x = 698,002.31
5. Step 5: Solve for x
   x = 698,002.31/1,056.78
6. Step 6: Final answer
   x = 660.50