Finding the Fourth Proportional to 1,385.48, 2,078.76 and 411.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.48 : 2,078.76 = 411.59 : x
2. Step 2: Convert to fraction form
   1,385.48/2,078.76 = 411.59/x
3. Step 3: Cross multiply
   1,385.48x = 2,078.76 × 411.59
4. Step 4: Simplify right side
   1,385.48x = 855,596.83
5. Step 5: Solve for x
   x = 855,596.83/1,385.48
6. Step 6: Final answer
   x = 617.55