Finding the Fourth Proportional to 1,131.25, 1,560.63 and 688.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.25 : 1,560.63 = 688.39 : x
2. Step 2: Convert to fraction form
   1,131.25/1,560.63 = 688.39/x
3. Step 3: Cross multiply
   1,131.25x = 1,560.63 × 688.39
4. Step 4: Simplify right side
   1,131.25x = 1,074,322.09
5. Step 5: Solve for x
   x = 1,074,322.09/1,131.25
6. Step 6: Final answer
   x = 949.68