Use pythagoras since it has a right angle ma boi
the formula for that is a^2 + b^2 + c^2
therefore 2sqrt(3)^2 - sqrt(3)^2 = (the missing side length)^2
2sqrt(3)^2 = 6 and sqrt(3)^2 =3
6- 3 = 2
bu then you have to sqrt your answer which means you have sqrt 2 at the end
