Finding the Third Proportional to 420,309 and 628,978

Step by Step Solution

1. Step 1: Write the proportion equation
   420,309 : 628,978 = 628,978 : x
2. Step 2: Convert to fraction form
   420,309/628,978 = 628,978/x
3. Step 3: Cross multiply
   420,309x = 628,978 × 628,978
4. Step 4: Simplify right side
   420,309x = 395,613,324,484
5. Step 5: Solve for x
   x = 395,613,324,484/420,309
6. Step 6: Final answer
   x = 941,244.00