Finding the Fourth Proportional to 1,211.84, 1,672.28 and 687.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,211.84 : 1,672.28 = 687.86 : x
2. Step 2: Convert to fraction form
   1,211.84/1,672.28 = 687.86/x
3. Step 3: Cross multiply
   1,211.84x = 1,672.28 × 687.86
4. Step 4: Simplify right side
   1,211.84x = 1,150,294.52
5. Step 5: Solve for x
   x = 1,150,294.52/1,211.84
6. Step 6: Final answer
   x = 949.21