Finding the Fourth Proportional to 1,003.79, 1,385.31 and 561.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,003.79 : 1,385.31 = 561.68 : x
2. Step 2: Convert to fraction form
   1,003.79/1,385.31 = 561.68/x
3. Step 3: Cross multiply
   1,003.79x = 1,385.31 × 561.68
4. Step 4: Simplify right side
   1,003.79x = 778,100.92
5. Step 5: Solve for x
   x = 778,100.92/1,003.79
6. Step 6: Final answer
   x = 775.17