Finding the Fourth Proportional to 1,397.35, 1,929.10 and 978.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.35 : 1,929.10 = 978.98 : x
2. Step 2: Convert to fraction form
   1,397.35/1,929.10 = 978.98/x
3. Step 3: Cross multiply
   1,397.35x = 1,929.10 × 978.98
4. Step 4: Simplify right side
   1,397.35x = 1,888,550.32
5. Step 5: Solve for x
   x = 1,888,550.32/1,397.35
6. Step 6: Final answer
   x = 1,351.53