Finding the Fourth Proportional to 1,003.89, 1,385.18 and 561.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,003.89 : 1,385.18 = 561.71 : x
2. Step 2: Convert to fraction form
   1,003.89/1,385.18 = 561.71/x
3. Step 3: Cross multiply
   1,003.89x = 1,385.18 × 561.71
4. Step 4: Simplify right side
   1,003.89x = 778,066.74
5. Step 5: Solve for x
   x = 778,066.74/1,003.89
6. Step 6: Final answer
   x = 775.05