Finding the Fourth Proportional to 2,618.72, 3,613.73 and 1,439.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,618.72 : 3,613.73 = 1,439.78 : x
2. Step 2: Convert to fraction form
   2,618.72/3,613.73 = 1,439.78/x
3. Step 3: Cross multiply
   2,618.72x = 3,613.73 × 1,439.78
4. Step 4: Simplify right side
   2,618.72x = 5,202,976.18
5. Step 5: Solve for x
   x = 5,202,976.18/2,618.72
6. Step 6: Final answer
   x = 1,986.84