Finding the Fourth Proportional to 1,131.27, 1,560.59 and 688.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.27 : 1,560.59 = 688.40 : x
2. Step 2: Convert to fraction form
   1,131.27/1,560.59 = 688.40/x
3. Step 3: Cross multiply
   1,131.27x = 1,560.59 × 688.40
4. Step 4: Simplify right side
   1,131.27x = 1,074,309.28
5. Step 5: Solve for x
   x = 1,074,309.28/1,131.27
6. Step 6: Final answer
   x = 949.65