Finding the Fourth Proportional to 2,558.74, 3,530.91 and 1,439.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,558.74 : 3,530.91 = 1,439.72 : x
2. Step 2: Convert to fraction form
   2,558.74/3,530.91 = 1,439.72/x
3. Step 3: Cross multiply
   2,558.74x = 3,530.91 × 1,439.72
4. Step 4: Simplify right side
   2,558.74x = 5,083,521.75
5. Step 5: Solve for x
   x = 5,083,521.75/2,558.74
6. Step 6: Final answer
   x = 1,986.73