Finding the Fourth Proportional to 2,178.32, 3,265.25 and 861.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,178.32 : 3,265.25 = 861.55 : x
2. Step 2: Convert to fraction form
   2,178.32/3,265.25 = 861.55/x
3. Step 3: Cross multiply
   2,178.32x = 3,265.25 × 861.55
4. Step 4: Simplify right side
   2,178.32x = 2,813,155.50
5. Step 5: Solve for x
   x = 2,813,155.50/2,178.32
6. Step 6: Final answer
   x = 1,291.43