Compare to

 and find that

, , and 

Then substitute in

 

 





216 is not a perfect square. However it has a perfect square
36 as a factor for 36*6 is 216. So we write 36*6 instead of 216



Now to take the square root of the product 36*6 by taking individual 
square roots of 36 and 6



Now we know the square root of 36 is 6, so we write 6 instead of .



Next we factor 6 out of the top:



Finally we cancel the 6 in the top into the 18 in the bottom 



That leaves 3 in the bottom:



Edwin