Finding the Third Proportional to 331.69 and 520.31

Step by Step Solution

1. Step 1: Write the proportion equation
   331.69 : 520.31 = 520.31 : x
2. Step 2: Convert to fraction form
   331.69/520.31 = 520.31/x
3. Step 3: Cross multiply
   331.69x = 520.31 × 520.31
4. Step 4: Simplify right side
   331.69x = 270,725.10
5. Step 5: Solve for x
   x = 270,725.10/331.69
6. Step 6: Final answer
   x = 816.21