Finding the Fourth Proportional to 1,079.25, 1,617.85 and 688.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,079.25 : 1,617.85 = 688.15 : x
2. Step 2: Convert to fraction form
   1,079.25/1,617.85 = 688.15/x
3. Step 3: Cross multiply
   1,079.25x = 1,617.85 × 688.15
4. Step 4: Simplify right side
   1,079.25x = 1,113,323.78
5. Step 5: Solve for x
   x = 1,113,323.78/1,079.25
6. Step 6: Final answer
   x = 1,031.57