Finding the Fourth Proportional to 1,081.33, 1,492.17 and 639.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.33 : 1,492.17 = 639.07 : x
2. Step 2: Convert to fraction form
   1,081.33/1,492.17 = 639.07/x
3. Step 3: Cross multiply
   1,081.33x = 1,492.17 × 639.07
4. Step 4: Simplify right side
   1,081.33x = 953,606.94
5. Step 5: Solve for x
   x = 953,606.94/1,081.33
6. Step 6: Final answer
   x = 881.88