Finding the Fourth Proportional to 3,900.09, 5,849.74 and 978.40

Step by Step Solution

1. Step 1: Write the proportion equation
   3,900.09 : 5,849.74 = 978.40 : x
2. Step 2: Convert to fraction form
   3,900.09/5,849.74 = 978.40/x
3. Step 3: Cross multiply
   3,900.09x = 5,849.74 × 978.40
4. Step 4: Simplify right side
   3,900.09x = 5,723,385.62
5. Step 5: Solve for x
   x = 5,723,385.62/3,900.09
6. Step 6: Final answer
   x = 1,467.50