Finding the Fourth Proportional to 1,025.57, 1,536.89 and 439.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,025.57 : 1,536.89 = 439.76 : x
2. Step 2: Convert to fraction form
   1,025.57/1,536.89 = 439.76/x
3. Step 3: Cross multiply
   1,025.57x = 1,536.89 × 439.76
4. Step 4: Simplify right side
   1,025.57x = 675,852.86
5. Step 5: Solve for x
   x = 675,852.86/1,025.57
6. Step 6: Final answer
   x = 659.01