Finding the Third Proportional to 211,810 and 412,978

Step by Step Solution

1. Step 1: Write the proportion equation
   211,810 : 412,978 = 412,978 : x
2. Step 2: Convert to fraction form
   211,810/412,978 = 412,978/x
3. Step 3: Cross multiply
   211,810x = 412,978 × 412,978
4. Step 4: Simplify right side
   211,810x = 170,550,828,484
5. Step 5: Solve for x
   x = 170,550,828,484/211,810
6. Step 6: Final answer
   x = 805,206.69