Diagram not drawn accurately 110 work out the size of the angle marked y give a reason for your answer.

M∠1 + m∠2 + m∠3 = 360
         y + 110 + 90 = 360
                 y + 200 = 360
                     - 200 - 200 
                           y = 160

It is the answer because it shows that the first one is 110 degrees and the second one 90 degrees, making a total of 200 degrees; since the angles have a total of 360 degrees, the value of y is 160 degrees.