Cotangent

The sum of the measures of the angles of a quadrilateral is 360º.

x+y+z+w=360º

Find the value of x in the quadrilateral

Since the sum of the angle measures in a quadrilateral is 360º, x+65+85+90=360

Since the sum of the angle measures in a quadrilateral is 360º, x+106+131+67=360

So, the value of x is 56º.