Finding the Third Proportional to 417.47 and 685.69

Step by Step Solution

1. Step 1: Write the proportion equation
   417.47 : 685.69 = 685.69 : x
2. Step 2: Convert to fraction form
   417.47/685.69 = 685.69/x
3. Step 3: Cross multiply
   417.47x = 685.69 × 685.69
4. Step 4: Simplify right side
   417.47x = 470,167.35
5. Step 5: Solve for x
   x = 470,167.35/417.47
6. Step 6: Final answer
   x = 1,126.23