Finding the Fourth Proportional to 2,807.50, 4,212.18 and 859.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,807.50 : 4,212.18 = 859.72 : x
2. Step 2: Convert to fraction form
   2,807.50/4,212.18 = 859.72/x
3. Step 3: Cross multiply
   2,807.50x = 4,212.18 × 859.72
4. Step 4: Simplify right side
   2,807.50x = 3,621,295.39
5. Step 5: Solve for x
   x = 3,621,295.39/2,807.50
6. Step 6: Final answer
   x = 1,289.86