Finding the Fourth Proportional to 1,080.34, 1,491.41 and 687.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,080.34 : 1,491.41 = 687.89 : x
2. Step 2: Convert to fraction form
   1,080.34/1,491.41 = 687.89/x
3. Step 3: Cross multiply
   1,080.34x = 1,491.41 × 687.89
4. Step 4: Simplify right side
   1,080.34x = 1,025,931.47
5. Step 5: Solve for x
   x = 1,025,931.47/1,080.34
6. Step 6: Final answer
   x = 949.64