Finding the Fourth Proportional to 1,081.59, 1,492.11 and 639.33

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.59 : 1,492.11 = 639.33 : x
2. Step 2: Convert to fraction form
   1,081.59/1,492.11 = 639.33/x
3. Step 3: Cross multiply
   1,081.59x = 1,492.11 × 639.33
4. Step 4: Simplify right side
   1,081.59x = 953,950.69
5. Step 5: Solve for x
   x = 953,950.69/1,081.59
6. Step 6: Final answer
   x = 881.99