Finding the Fourth Proportional to 1,647.60, 2,469.24 and 857.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,647.60 : 2,469.24 = 857.31 : x
2. Step 2: Convert to fraction form
   1,647.60/2,469.24 = 857.31/x
3. Step 3: Cross multiply
   1,647.60x = 2,469.24 × 857.31
4. Step 4: Simplify right side
   1,647.60x = 2,116,904.14
5. Step 5: Solve for x
   x = 2,116,904.14/1,647.60
6. Step 6: Final answer
   x = 1,284.84