Finding the Fourth Proportional to 1,396.85, 1,928.41 and 978.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,396.85 : 1,928.41 = 978.48 : x
2. Step 2: Convert to fraction form
   1,396.85/1,928.41 = 978.48/x
3. Step 3: Cross multiply
   1,396.85x = 1,928.41 × 978.48
4. Step 4: Simplify right side
   1,396.85x = 1,886,908.17
5. Step 5: Solve for x
   x = 1,886,908.17/1,396.85
6. Step 6: Final answer
   x = 1,350.84