Finding the Fourth Proportional to 2,618.21, 3,613.15 and 1,439.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,618.21 : 3,613.15 = 1,439.30 : x
2. Step 2: Convert to fraction form
   2,618.21/3,613.15 = 1,439.30/x
3. Step 3: Cross multiply
   2,618.21x = 3,613.15 × 1,439.30
4. Step 4: Simplify right side
   2,618.21x = 5,200,406.80
5. Step 5: Solve for x
   x = 5,200,406.80/2,618.21
6. Step 6: Final answer
   x = 1,986.25