Finding the Third Proportional to 219.38 and 406.69

Step by Step Solution

1. Step 1: Write the proportion equation
   219.38 : 406.69 = 406.69 : x
2. Step 2: Convert to fraction form
   219.38/406.69 = 406.69/x
3. Step 3: Cross multiply
   219.38x = 406.69 × 406.69
4. Step 4: Simplify right side
   219.38x = 165,394.72
5. Step 5: Solve for x
   x = 165,394.72/219.38
6. Step 6: Final answer
   x = 753.94