Finding the Fourth Proportional to 2,558.76, 3,531.26 and 1,439.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,558.76 : 3,531.26 = 1,439.78 : x
2. Step 2: Convert to fraction form
   2,558.76/3,531.26 = 1,439.78/x
3. Step 3: Cross multiply
   2,558.76x = 3,531.26 × 1,439.78
4. Step 4: Simplify right side
   2,558.76x = 5,084,223.47
5. Step 5: Solve for x
   x = 5,084,223.47/2,558.76
6. Step 6: Final answer
   x = 1,986.99