Finding the Fourth Proportional to 1,383.16, 1,906.86 and 989.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,383.16 : 1,906.86 = 989.50 : x
2. Step 2: Convert to fraction form
   1,383.16/1,906.86 = 989.50/x
3. Step 3: Cross multiply
   1,383.16x = 1,906.86 × 989.50
4. Step 4: Simplify right side
   1,383.16x = 1,886,837.97
5. Step 5: Solve for x
   x = 1,886,837.97/1,383.16
6. Step 6: Final answer
   x = 1,364.15