Finding the Fourth Proportional to 1,081.67, 1,492.58 and 639.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.67 : 1,492.58 = 639.41 : x
2. Step 2: Convert to fraction form
   1,081.67/1,492.58 = 639.41/x
3. Step 3: Cross multiply
   1,081.67x = 1,492.58 × 639.41
4. Step 4: Simplify right side
   1,081.67x = 954,359.92
5. Step 5: Solve for x
   x = 954,359.92/1,081.67
6. Step 6: Final answer
   x = 882.31