Finding the Fourth Proportional to 1,397.82, 1,928.49 and 978.84

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.82 : 1,928.49 = 978.84 : x
2. Step 2: Convert to fraction form
   1,397.82/1,928.49 = 978.84/x
3. Step 3: Cross multiply
   1,397.82x = 1,928.49 × 978.84
4. Step 4: Simplify right side
   1,397.82x = 1,887,683.15
5. Step 5: Solve for x
   x = 1,887,683.15/1,397.82
6. Step 6: Final answer
   x = 1,350.45