Finding the Fourth Proportional to 2,576.39, 3,864.86 and 820.98

Step by Step Solution

1. Step 1: Write the proportion equation
   2,576.39 : 3,864.86 = 820.98 : x
2. Step 2: Convert to fraction form
   2,576.39/3,864.86 = 820.98/x
3. Step 3: Cross multiply
   2,576.39x = 3,864.86 × 820.98
4. Step 4: Simplify right side
   2,576.39x = 3,172,976.35
5. Step 5: Solve for x
   x = 3,172,976.35/2,576.39
6. Step 6: Final answer
   x = 1,231.56