Finding the Third Proportional to 422,608 and 620,978

Step by Step Solution

1. Step 1: Write the proportion equation
   422,608 : 620,978 = 620,978 : x
2. Step 2: Convert to fraction form
   422,608/620,978 = 620,978/x
3. Step 3: Cross multiply
   422,608x = 620,978 × 620,978
4. Step 4: Simplify right side
   422,608x = 385,613,676,484
5. Step 5: Solve for x
   x = 385,613,676,484/422,608
6. Step 6: Final answer
   x = 912,461.85