Finding the Fourth Proportional to 1,105.12, 1,521.60 and 938.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.12 : 1,521.60 = 938.96 : x
2. Step 2: Convert to fraction form
   1,105.12/1,521.60 = 938.96/x
3. Step 3: Cross multiply
   1,105.12x = 1,521.60 × 938.96
4. Step 4: Simplify right side
   1,105.12x = 1,428,721.54
5. Step 5: Solve for x
   x = 1,428,721.54/1,105.12
6. Step 6: Final answer
   x = 1,292.82