Finding the Fourth Proportional to 1,080.39, 1,490.71 and 687.27

Step by Step Solution

1. Step 1: Write the proportion equation
   1,080.39 : 1,490.71 = 687.27 : x
2. Step 2: Convert to fraction form
   1,080.39/1,490.71 = 687.27/x
3. Step 3: Cross multiply
   1,080.39x = 1,490.71 × 687.27
4. Step 4: Simplify right side
   1,080.39x = 1,024,520.26
5. Step 5: Solve for x
   x = 1,024,520.26/1,080.39
6. Step 6: Final answer
   x = 948.29