Finding the Fourth Proportional to 2,590.72, 3,886.26 and 860.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,590.72 : 3,886.26 = 860.56 : x
2. Step 2: Convert to fraction form
   2,590.72/3,886.26 = 860.56/x
3. Step 3: Cross multiply
   2,590.72x = 3,886.26 × 860.56
4. Step 4: Simplify right side
   2,590.72x = 3,344,359.91
5. Step 5: Solve for x
   x = 3,344,359.91/2,590.72
6. Step 6: Final answer
   x = 1,290.90