Finding the Fourth Proportional to 2,591.50, 3,887.86 and 860.13

Step by Step Solution

1. Step 1: Write the proportion equation
   2,591.50 : 3,887.86 = 860.13 : x
2. Step 2: Convert to fraction form
   2,591.50/3,887.86 = 860.13/x
3. Step 3: Cross multiply
   2,591.50x = 3,887.86 × 860.13
4. Step 4: Simplify right side
   2,591.50x = 3,344,065.02
5. Step 5: Solve for x
   x = 3,344,065.02/2,591.50
6. Step 6: Final answer
   x = 1,290.40