Finding the Fourth Proportional to 1,641.57, 2,460.86 and 820.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,641.57 : 2,460.86 = 820.09 : x
2. Step 2: Convert to fraction form
   1,641.57/2,460.86 = 820.09/x
3. Step 3: Cross multiply
   1,641.57x = 2,460.86 × 820.09
4. Step 4: Simplify right side
   1,641.57x = 2,018,126.68
5. Step 5: Solve for x
   x = 2,018,126.68/1,641.57
6. Step 6: Final answer
   x = 1,229.39