Finding the Fourth Proportional to 1,103.31, 1,645.65 and 939.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,103.31 : 1,645.65 = 939.15 : x
2. Step 2: Convert to fraction form
   1,103.31/1,645.65 = 939.15/x
3. Step 3: Cross multiply
   1,103.31x = 1,645.65 × 939.15
4. Step 4: Simplify right side
   1,103.31x = 1,545,512.20
5. Step 5: Solve for x
   x = 1,545,512.20/1,103.31
6. Step 6: Final answer
   x = 1,400.80