Finding the Fourth Proportional to 2,578.31, 3,867.69 and 823.39

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.31 : 3,867.69 = 823.39 : x
2. Step 2: Convert to fraction form
   2,578.31/3,867.69 = 823.39/x
3. Step 3: Cross multiply
   2,578.31x = 3,867.69 × 823.39
4. Step 4: Simplify right side
   2,578.31x = 3,184,615.78
5. Step 5: Solve for x
   x = 3,184,615.78/2,578.31
6. Step 6: Final answer
   x = 1,235.16