Finding the Fourth Proportional to 1,065.27, 1,470.26 and 639.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,065.27 : 1,470.26 = 639.78 : x
2. Step 2: Convert to fraction form
   1,065.27/1,470.26 = 639.78/x
3. Step 3: Cross multiply
   1,065.27x = 1,470.26 × 639.78
4. Step 4: Simplify right side
   1,065.27x = 940,639.03
5. Step 5: Solve for x
   x = 940,639.03/1,065.27
6. Step 6: Final answer
   x = 883.00