Finding the Fourth Proportional to 1,404.30, 2,102.40 and 857.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,404.30 : 2,102.40 = 857.55 : x
2. Step 2: Convert to fraction form
   1,404.30/2,102.40 = 857.55/x
3. Step 3: Cross multiply
   1,404.30x = 2,102.40 × 857.55
4. Step 4: Simplify right side
   1,404.30x = 1,802,913.12
5. Step 5: Solve for x
   x = 1,802,913.12/1,404.30
6. Step 6: Final answer
   x = 1,283.85