Finding the Third Proportional to 321.52 and 691.83

Step by Step Solution

1. Step 1: Write the proportion equation
   321.52 : 691.83 = 691.83 : x
2. Step 2: Convert to fraction form
   321.52/691.83 = 691.83/x
3. Step 3: Cross multiply
   321.52x = 691.83 × 691.83
4. Step 4: Simplify right side
   321.52x = 478,626.15
5. Step 5: Solve for x
   x = 478,626.15/321.52
6. Step 6: Final answer
   x = 1,488.66