Finding the Third Proportional to 422.72 and 622.69

Step by Step Solution

1. Step 1: Write the proportion equation
   422.72 : 622.69 = 622.69 : x
2. Step 2: Convert to fraction form
   422.72/622.69 = 622.69/x
3. Step 3: Cross multiply
   422.72x = 622.69 × 622.69
4. Step 4: Simplify right side
   422.72x = 387,739.72
5. Step 5: Solve for x
   x = 387,739.72/422.72
6. Step 6: Final answer
   x = 917.25