Finding the Fourth Proportional to 1,212.01, 1,672.58 and 688.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,212.01 : 1,672.58 = 688.05 : x
2. Step 2: Convert to fraction form
   1,212.01/1,672.58 = 688.05/x
3. Step 3: Cross multiply
   1,212.01x = 1,672.58 × 688.05
4. Step 4: Simplify right side
   1,212.01x = 1,150,818.67
5. Step 5: Solve for x
   x = 1,150,818.67/1,212.01
6. Step 6: Final answer
   x = 949.51