Finding the Fourth Proportional to 1,081.34, 1,491.72 and 639.14

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.34 : 1,491.72 = 639.14 : x
2. Step 2: Convert to fraction form
   1,081.34/1,491.72 = 639.14/x
3. Step 3: Cross multiply
   1,081.34x = 1,491.72 × 639.14
4. Step 4: Simplify right side
   1,081.34x = 953,417.92
5. Step 5: Solve for x
   x = 953,417.92/1,081.34
6. Step 6: Final answer
   x = 881.70