Finding the Fourth Proportional to 1,081.88, 1,493.04 and 640.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.88 : 1,493.04 = 640.04 : x
2. Step 2: Convert to fraction form
   1,081.88/1,493.04 = 640.04/x
3. Step 3: Cross multiply
   1,081.88x = 1,493.04 × 640.04
4. Step 4: Simplify right side
   1,081.88x = 955,605.32
5. Step 5: Solve for x
   x = 955,605.32/1,081.88
6. Step 6: Final answer
   x = 883.28