Finding the Fourth Proportional to 1,003.72, 1,385.10 and 561.67

Step by Step Solution

1. Step 1: Write the proportion equation
   1,003.72 : 1,385.10 = 561.67 : x
2. Step 2: Convert to fraction form
   1,003.72/1,385.10 = 561.67/x
3. Step 3: Cross multiply
   1,003.72x = 1,385.10 × 561.67
4. Step 4: Simplify right side
   1,003.72x = 777,969.12
5. Step 5: Solve for x
   x = 777,969.12/1,003.72
6. Step 6: Final answer
   x = 775.09