Explanation:
if you draw an imaginary perpendicular line across the figure from the vertex which joins the line of 2 cm with the line that is making an angle of X then you can see that this figure is made up of two figures that is a triangle and a rectangle.
now from the angle given i.e X.
perpendicular= 5 cm
base = 14 -2= 12 cm
hypotenuse= ?
we know that,
h² = p²+b²
= 5²+12²=169
h= √169
h= 13
again,
cos X = b/h
= 12/13