Finding the Fourth Proportional to 1,247.94, 1,722.20 and 688.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,247.94 : 1,722.20 = 688.37 : x
2. Step 2: Convert to fraction form
   1,247.94/1,722.20 = 688.37/x
3. Step 3: Cross multiply
   1,247.94x = 1,722.20 × 688.37
4. Step 4: Simplify right side
   1,247.94x = 1,185,498.76
5. Step 5: Solve for x
   x = 1,185,498.76/1,247.94
6. Step 6: Final answer
   x = 949.96