Finding the Fourth Proportional to 1,211.97, 1,672.55 and 688.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,211.97 : 1,672.55 = 688.04 : x
2. Step 2: Convert to fraction form
   1,211.97/1,672.55 = 688.04/x
3. Step 3: Cross multiply
   1,211.97x = 1,672.55 × 688.04
4. Step 4: Simplify right side
   1,211.97x = 1,150,781.30
5. Step 5: Solve for x
   x = 1,150,781.30/1,211.97
6. Step 6: Final answer
   x = 949.51