Finding the Fourth Proportional to 3,900.60, 5,850.72 and 978.84

Step by Step Solution

1. Step 1: Write the proportion equation
   3,900.60 : 5,850.72 = 978.84 : x
2. Step 2: Convert to fraction form
   3,900.60/5,850.72 = 978.84/x
3. Step 3: Cross multiply
   3,900.60x = 5,850.72 × 978.84
4. Step 4: Simplify right side
   3,900.60x = 5,726,918.76
5. Step 5: Solve for x
   x = 5,726,918.76/3,900.60
6. Step 6: Final answer
   x = 1,468.21