Finding the Fourth Proportional to 1,162.38, 1,603.94 and 638.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,162.38 : 1,603.94 = 638.40 : x
2. Step 2: Convert to fraction form
   1,162.38/1,603.94 = 638.40/x
3. Step 3: Cross multiply
   1,162.38x = 1,603.94 × 638.40
4. Step 4: Simplify right side
   1,162.38x = 1,023,952.10
5. Step 5: Solve for x
   x = 1,023,952.10/1,162.38
6. Step 6: Final answer
   x = 880.91