Finding the Third Proportional to 99,978 and 213,204

Step by Step Solution

1. Step 1: Write the proportion equation
   99,978 : 213,204 = 213,204 : x
2. Step 2: Convert to fraction form
   99,978/213,204 = 213,204/x
3. Step 3: Cross multiply
   99,978x = 213,204 × 213,204
4. Step 4: Simplify right side
   99,978x = 45,455,945,616
5. Step 5: Solve for x
   x = 45,455,945,616/99,978
6. Step 6: Final answer
   x = 454,659.48