Finding the Fourth Proportional to 2,139.56, 2,951.70 and 1,439.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.56 : 2,951.70 = 1,439.72 : x
2. Step 2: Convert to fraction form
   2,139.56/2,951.70 = 1,439.72/x
3. Step 3: Cross multiply
   2,139.56x = 2,951.70 × 1,439.72
4. Step 4: Simplify right side
   2,139.56x = 4,249,621.52
5. Step 5: Solve for x
   x = 4,249,621.52/2,139.56
6. Step 6: Final answer
   x = 1,986.21