First one :
We know an opposite side and an adjacent side....the tangent seems most appropriate, here
So we have
tan x = 11/9 use the tan inverse (atan) to find x
atan (11/9) = x ≈ 50.71° = 51°
Second one....
tan Y = 6/7 tan Z = 7/6
Third one :
We know an angle, the hypotenuse and we are looking for an adjacent side to the angle....the cosine is what we need
cos (26) = x / 10 multiply both sides by 10
10 cos (26) = x ≈ 9
Fourth one :
We know an angle, the adjacent side....and we are looking for the hypotenuse....the cosine, again....
cos36 = 12 / x divide both sides by cos 36......multiply both sides by x
x = 12 / cos 36 ≈ 14.8
Last one
We know an angle, an adjacent side....and we are looking for the opposite side.....the tangent seems good
tan 40 = x / 5 multiply both sides by 5
5 tan (40) = x ≈ 4.2