Finding the Fourth Proportional to 1,081.92, 1,492.82 and 639.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.92 : 1,492.82 = 639.74 : x
2. Step 2: Convert to fraction form
   1,081.92/1,492.82 = 639.74/x
3. Step 3: Cross multiply
   1,081.92x = 1,492.82 × 639.74
4. Step 4: Simplify right side
   1,081.92x = 955,016.67
5. Step 5: Solve for x
   x = 955,016.67/1,081.92
6. Step 6: Final answer
   x = 882.71