Finding the Fourth Proportional to 1,211.82, 1,672.20 and 687.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,211.82 : 1,672.20 = 687.75 : x
2. Step 2: Convert to fraction form
   1,211.82/1,672.20 = 687.75/x
3. Step 3: Cross multiply
   1,211.82x = 1,672.20 × 687.75
4. Step 4: Simplify right side
   1,211.82x = 1,150,055.55
5. Step 5: Solve for x
   x = 1,150,055.55/1,211.82
6. Step 6: Final answer
   x = 949.03