Finding the Fourth Proportional to 865.69, 1,289.52 and 826.40

Step by Step Solution

1. Step 1: Write the proportion equation
   865.69 : 1,289.52 = 826.40 : x
2. Step 2: Convert to fraction form
   865.69/1,289.52 = 826.40/x
3. Step 3: Cross multiply
   865.69x = 1,289.52 × 826.40
4. Step 4: Simplify right side
   865.69x = 1,065,662.55
5. Step 5: Solve for x
   x = 1,065,662.55/865.69
6. Step 6: Final answer
   x = 1,231.00