Finding the Fourth Proportional to 1,040.91, 1,561.47 and 485.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,040.91 : 1,561.47 = 485.50 : x
2. Step 2: Convert to fraction form
   1,040.91/1,561.47 = 485.50/x
3. Step 3: Cross multiply
   1,040.91x = 1,561.47 × 485.50
4. Step 4: Simplify right side
   1,040.91x = 758,093.69
5. Step 5: Solve for x
   x = 758,093.69/1,040.91
6. Step 6: Final answer
   x = 728.30