Finding the Fourth Proportional to 1,402.62, 2,105.55 and 858.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,402.62 : 2,105.55 = 858.30 : x
2. Step 2: Convert to fraction form
   1,402.62/2,105.55 = 858.30/x
3. Step 3: Cross multiply
   1,402.62x = 2,105.55 × 858.30
4. Step 4: Simplify right side
   1,402.62x = 1,807,193.57
5. Step 5: Solve for x
   x = 1,807,193.57/1,402.62
6. Step 6: Final answer
   x = 1,288.44