Finding the Fourth Proportional to 2,439.40, 3,658.26 and 978.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,439.40 : 3,658.26 = 978.12 : x
2. Step 2: Convert to fraction form
   2,439.40/3,658.26 = 978.12/x
3. Step 3: Cross multiply
   2,439.40x = 3,658.26 × 978.12
4. Step 4: Simplify right side
   2,439.40x = 3,578,217.27
5. Step 5: Solve for x
   x = 3,578,217.27/2,439.40
6. Step 6: Final answer
   x = 1,466.84