Finding the Fourth Proportional to 1,081.04, 1,491.82 and 638.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.04 : 1,491.82 = 638.91 : x
2. Step 2: Convert to fraction form
   1,081.04/1,491.82 = 638.91/x
3. Step 3: Cross multiply
   1,081.04x = 1,491.82 × 638.91
4. Step 4: Simplify right side
   1,081.04x = 953,137.12
5. Step 5: Solve for x
   x = 953,137.12/1,081.04
6. Step 6: Final answer
   x = 881.69