see the attached picture to better understand the problem
we know that
if XZ = YZ
then
XYZ is an isosceles triangle
m ∠ Z=74°
m ∠ X= m ∠ Y
m ∠ X=(180°-74°)/2-----> m ∠ X=53°
applying the law of sines
XZ/sin 53°=XY/sin 74°
XZ=(sin 53°/sin 74°)*XY
XZ=0.83*XY
therefore
XZ < XY or XY > XZ
the answer is
The longest side of the triangle is XY