Finding the Fourth Proportional to 1,040.88, 1,435.89 and 621.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,040.88 : 1,435.89 = 621.10 : x
2. Step 2: Convert to fraction form
   1,040.88/1,435.89 = 621.10/x
3. Step 3: Cross multiply
   1,040.88x = 1,435.89 × 621.10
4. Step 4: Simplify right side
   1,040.88x = 891,831.28
5. Step 5: Solve for x
   x = 891,831.28/1,040.88
6. Step 6: Final answer
   x = 856.81