Finding the Third Proportional to 320.92 and 691.89

Step by Step Solution

1. Step 1: Write the proportion equation
   320.92 : 691.89 = 691.89 : x
2. Step 2: Convert to fraction form
   320.92/691.89 = 691.89/x
3. Step 3: Cross multiply
   320.92x = 691.89 × 691.89
4. Step 4: Simplify right side
   320.92x = 478,713.82
5. Step 5: Solve for x
   x = 478,713.82/320.92
6. Step 6: Final answer
   x = 1,491.67