Finding the Fourth Proportional to 2,591.74, 3,887.85 and 860.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,591.74 : 3,887.85 = 860.50 : x
2. Step 2: Convert to fraction form
   2,591.74/3,887.85 = 860.50/x
3. Step 3: Cross multiply
   2,591.74x = 3,887.85 × 860.50
4. Step 4: Simplify right side
   2,591.74x = 3,345,494.93
5. Step 5: Solve for x
   x = 3,345,494.93/2,591.74
6. Step 6: Final answer
   x = 1,290.83