Finding the Fourth Proportional to 1,081.54, 1,492.47 and 639.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.54 : 1,492.47 = 639.49 : x
2. Step 2: Convert to fraction form
   1,081.54/1,492.47 = 639.49/x
3. Step 3: Cross multiply
   1,081.54x = 1,492.47 × 639.49
4. Step 4: Simplify right side
   1,081.54x = 954,408.98
5. Step 5: Solve for x
   x = 954,408.98/1,081.54
6. Step 6: Final answer
   x = 882.45