Finding the Fourth Proportional to 1,003.92, 1,385.37 and 555.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,003.92 : 1,385.37 = 555.81 : x
2. Step 2: Convert to fraction form
   1,003.92/1,385.37 = 555.81/x
3. Step 3: Cross multiply
   1,003.92x = 1,385.37 × 555.81
4. Step 4: Simplify right side
   1,003.92x = 769,995.57
5. Step 5: Solve for x
   x = 769,995.57/1,003.92
6. Step 6: Final answer
   x = 766.99