Finding the Fourth Proportional to 2,807.86, 4,212.59 and 860.35

Step by Step Solution

1. Step 1: Write the proportion equation
   2,807.86 : 4,212.59 = 860.35 : x
2. Step 2: Convert to fraction form
   2,807.86/4,212.59 = 860.35/x
3. Step 3: Cross multiply
   2,807.86x = 4,212.59 × 860.35
4. Step 4: Simplify right side
   2,807.86x = 3,624,282.89
5. Step 5: Solve for x
   x = 3,624,282.89/2,807.86
6. Step 6: Final answer
   x = 1,290.77