Finding the Fourth Proportional to 865.86, 1,300.80 and 819.24

Step by Step Solution

1. Step 1: Write the proportion equation
   865.86 : 1,300.80 = 819.24 : x
2. Step 2: Convert to fraction form
   865.86/1,300.80 = 819.24/x
3. Step 3: Cross multiply
   865.86x = 1,300.80 × 819.24
4. Step 4: Simplify right side
   865.86x = 1,065,667.39
5. Step 5: Solve for x
   x = 1,065,667.39/865.86
6. Step 6: Final answer
   x = 1,230.76