Finding the Fourth Proportional to 1,247.95, 1,722.17 and 688.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,247.95 : 1,722.17 = 688.47 : x
2. Step 2: Convert to fraction form
   1,247.95/1,722.17 = 688.47/x
3. Step 3: Cross multiply
   1,247.95x = 1,722.17 × 688.47
4. Step 4: Simplify right side
   1,247.95x = 1,185,662.38
5. Step 5: Solve for x
   x = 1,185,662.38/1,247.95
6. Step 6: Final answer
   x = 950.09