Finding the Third Proportional to 156.09 and 322.31

Step by Step Solution

1. Step 1: Write the proportion equation
   156.09 : 322.31 = 322.31 : x
2. Step 2: Convert to fraction form
   156.09/322.31 = 322.31/x
3. Step 3: Cross multiply
   156.09x = 322.31 × 322.31
4. Step 4: Simplify right side
   156.09x = 103,885.35
5. Step 5: Solve for x
   x = 103,885.35/156.09
6. Step 6: Final answer
   x = 665.53