Using SOH CAH TOA
Sin =opposite/hypotenuse
that means opposite=2
Hypotenuse=3
Cos=Adjacent/Hypotenuse
Using Pythagorean theorem
Hyp^2=Opp^2 +Adj^2
3^2 =2^2+adj^2
9=4+adj^2
9-4=adj^2
5=adj^2
Taking the square root of both sides
√5=adj
:: cos=√5/3
