Finding the Fourth Proportional to 1,003.96, 1,385.42 and 561.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,003.96 : 1,385.42 = 561.79 : x
2. Step 2: Convert to fraction form
   1,003.96/1,385.42 = 561.79/x
3. Step 3: Cross multiply
   1,003.96x = 1,385.42 × 561.79
4. Step 4: Simplify right side
   1,003.96x = 778,309.39
5. Step 5: Solve for x
   x = 778,309.39/1,003.96
6. Step 6: Final answer
   x = 775.24