Finding the Fourth Proportional to 1,212.32, 1,672.89 and 688.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,212.32 : 1,672.89 = 688.25 : x
2. Step 2: Convert to fraction form
   1,212.32/1,672.89 = 688.25/x
3. Step 3: Cross multiply
   1,212.32x = 1,672.89 × 688.25
4. Step 4: Simplify right side
   1,212.32x = 1,151,366.54
5. Step 5: Solve for x
   x = 1,151,366.54/1,212.32
6. Step 6: Final answer
   x = 949.72