Finding the Fourth Proportional to 1,080.41, 1,491.03 and 638.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,080.41 : 1,491.03 = 638.15 : x
2. Step 2: Convert to fraction form
   1,080.41/1,491.03 = 638.15/x
3. Step 3: Cross multiply
   1,080.41x = 1,491.03 × 638.15
4. Step 4: Simplify right side
   1,080.41x = 951,493.34
5. Step 5: Solve for x
   x = 951,493.34/1,080.41
6. Step 6: Final answer
   x = 880.68