Finding the Third Proportional to 217.69 and 379.69

Step by Step Solution

1. Step 1: Write the proportion equation
   217.69 : 379.69 = 379.69 : x
2. Step 2: Convert to fraction form
   217.69/379.69 = 379.69/x
3. Step 3: Cross multiply
   217.69x = 379.69 × 379.69
4. Step 4: Simplify right side
   217.69x = 144,162.60
5. Step 5: Solve for x
   x = 144,162.60/217.69
6. Step 6: Final answer
   x = 662.25