Finding the Third Proportional to 215.72 and 324.56

Step by Step Solution

1. Step 1: Write the proportion equation
   215.72 : 324.56 = 324.56 : x
2. Step 2: Convert to fraction form
   215.72/324.56 = 324.56/x
3. Step 3: Cross multiply
   215.72x = 324.56 × 324.56
4. Step 4: Simplify right side
   215.72x = 105,340.82
5. Step 5: Solve for x
   x = 105,340.82/215.72
6. Step 6: Final answer
   x = 488.32