Finding the Third Proportional to 321.75 and 513.38

Step by Step Solution

1. Step 1: Write the proportion equation
   321.75 : 513.38 = 513.38 : x
2. Step 2: Convert to fraction form
   321.75/513.38 = 513.38/x
3. Step 3: Cross multiply
   321.75x = 513.38 × 513.38
4. Step 4: Simplify right side
   321.75x = 263,553.89
5. Step 5: Solve for x
   x = 263,553.89/321.75
6. Step 6: Final answer
   x = 819.13