Finding the Fourth Proportional to 1,383.72, 1,909.94 and 911.97

Step by Step Solution

1. Step 1: Write the proportion equation
   1,383.72 : 1,909.94 = 911.97 : x
2. Step 2: Convert to fraction form
   1,383.72/1,909.94 = 911.97/x
3. Step 3: Cross multiply
   1,383.72x = 1,909.94 × 911.97
4. Step 4: Simplify right side
   1,383.72x = 1,741,793.87
5. Step 5: Solve for x
   x = 1,741,793.87/1,383.72
6. Step 6: Final answer
   x = 1,258.78