Finding the Fourth Proportional to 1,211.98, 1,672.50 and 688.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,211.98 : 1,672.50 = 688.18 : x
2. Step 2: Convert to fraction form
   1,211.98/1,672.50 = 688.18/x
3. Step 3: Cross multiply
   1,211.98x = 1,672.50 × 688.18
4. Step 4: Simplify right side
   1,211.98x = 1,150,981.05
5. Step 5: Solve for x
   x = 1,150,981.05/1,211.98
6. Step 6: Final answer
   x = 949.67