Finding the Fourth Proportional to 2,575.50, 3,863.31 and 820.47

Step by Step Solution

1. Step 1: Write the proportion equation
   2,575.50 : 3,863.31 = 820.47 : x
2. Step 2: Convert to fraction form
   2,575.50/3,863.31 = 820.47/x
3. Step 3: Cross multiply
   2,575.50x = 3,863.31 × 820.47
4. Step 4: Simplify right side
   2,575.50x = 3,169,729.96
5. Step 5: Solve for x
   x = 3,169,729.96/2,575.50
6. Step 6: Final answer
   x = 1,230.72