Finding the Fourth Proportional to 1,081.94, 1,493.26 and 639.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.94 : 1,493.26 = 639.86 : x
2. Step 2: Convert to fraction form
   1,081.94/1,493.26 = 639.86/x
3. Step 3: Cross multiply
   1,081.94x = 1,493.26 × 639.86
4. Step 4: Simplify right side
   1,081.94x = 955,477.34
5. Step 5: Solve for x
   x = 955,477.34/1,081.94
6. Step 6: Final answer
   x = 883.11