The first one can be done by Pythagoras theorem such as 
then 
then 
The second one can also done by Pythagoras theorem, note that this is isosceles triangle so
, again by using Pythagoras theorem 
then 
then 
For the last one can also done by property of 30-60-90 triangle.
The second one can also done by Pythagoras theorem, note that this is isosceles triangle so
For the last one can also done by property of 30-60-90 triangle.