Finding the Fourth Proportional to 2,618.63, 3,613.71 and 1,439.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,618.63 : 3,613.71 = 1,439.78 : x
2. Step 2: Convert to fraction form
   2,618.63/3,613.71 = 1,439.78/x
3. Step 3: Cross multiply
   2,618.63x = 3,613.71 × 1,439.78
4. Step 4: Simplify right side
   2,618.63x = 5,202,947.38
5. Step 5: Solve for x
   x = 5,202,947.38/2,618.63
6. Step 6: Final answer
   x = 1,986.90