Finding the Third Proportional to 206,428 and 314,978

Step by Step Solution

1. Step 1: Write the proportion equation
   206,428 : 314,978 = 314,978 : x
2. Step 2: Convert to fraction form
   206,428/314,978 = 314,978/x
3. Step 3: Cross multiply
   206,428x = 314,978 × 314,978
4. Step 4: Simplify right side
   206,428x = 99,211,140,484
5. Step 5: Solve for x
   x = 99,211,140,484/206,428
6. Step 6: Final answer
   x = 480,608.93