Finding the Fourth Proportional to 688.10, 1,026.50 and 669.27

Step by Step Solution

1. Step 1: Write the proportion equation
   688.10 : 1,026.50 = 669.27 : x
2. Step 2: Convert to fraction form
   688.10/1,026.50 = 669.27/x
3. Step 3: Cross multiply
   688.10x = 1,026.50 × 669.27
4. Step 4: Simplify right side
   688.10x = 687,002.31
5. Step 5: Solve for x
   x = 687,002.31/688.10
6. Step 6: Final answer
   x = 998.41