Finding the Fourth Proportional to 1,040.18, 1,561.01 and 391.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,040.18 : 1,561.01 = 391.10 : x
2. Step 2: Convert to fraction form
   1,040.18/1,561.01 = 391.10/x
3. Step 3: Cross multiply
   1,040.18x = 1,561.01 × 391.10
4. Step 4: Simplify right side
   1,040.18x = 610,501.25
5. Step 5: Solve for x
   x = 610,501.25/1,040.18
6. Step 6: Final answer
   x = 586.92