Finding the Fourth Proportional to 1,419.60, 1,960.20 and 978.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,419.60 : 1,960.20 = 978.96 : x
2. Step 2: Convert to fraction form
   1,419.60/1,960.20 = 978.96/x
3. Step 3: Cross multiply
   1,419.60x = 1,960.20 × 978.96
4. Step 4: Simplify right side
   1,419.60x = 1,918,957.39
5. Step 5: Solve for x
   x = 1,918,957.39/1,419.60
6. Step 6: Final answer
   x = 1,351.76