Finding the Fourth Proportional to 1,383.39, 1,906.45 and 989.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,383.39 : 1,906.45 = 989.73 : x
2. Step 2: Convert to fraction form
   1,383.39/1,906.45 = 989.73/x
3. Step 3: Cross multiply
   1,383.39x = 1,906.45 × 989.73
4. Step 4: Simplify right side
   1,383.39x = 1,886,868.28
5. Step 5: Solve for x
   x = 1,886,868.28/1,383.39
6. Step 6: Final answer
   x = 1,363.95