Finding the Fourth Proportional to 2,805.89, 4,208.86 and 858.09

Step by Step Solution

1. Step 1: Write the proportion equation
   2,805.89 : 4,208.86 = 858.09 : x
2. Step 2: Convert to fraction form
   2,805.89/4,208.86 = 858.09/x
3. Step 3: Cross multiply
   2,805.89x = 4,208.86 × 858.09
4. Step 4: Simplify right side
   2,805.89x = 3,611,597.53
5. Step 5: Solve for x
   x = 3,611,597.53/2,805.89
6. Step 6: Final answer
   x = 1,287.15