Finding the Fourth Proportional to 2,612.52, 3,919.20 and 857.01

Step by Step Solution

1. Step 1: Write the proportion equation
   2,612.52 : 3,919.20 = 857.01 : x
2. Step 2: Convert to fraction form
   2,612.52/3,919.20 = 857.01/x
3. Step 3: Cross multiply
   2,612.52x = 3,919.20 × 857.01
4. Step 4: Simplify right side
   2,612.52x = 3,358,793.59
5. Step 5: Solve for x
   x = 3,358,793.59/2,612.52
6. Step 6: Final answer
   x = 1,285.65