Finding the Fourth Proportional to 1,072.40, 1,480.83 and 680.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,072.40 : 1,480.83 = 680.12 : x
2. Step 2: Convert to fraction form
   1,072.40/1,480.83 = 680.12/x
3. Step 3: Cross multiply
   1,072.40x = 1,480.83 × 680.12
4. Step 4: Simplify right side
   1,072.40x = 1,007,142.10
5. Step 5: Solve for x
   x = 1,007,142.10/1,072.40
6. Step 6: Final answer
   x = 939.15