Hello Candidate,

Let one angle of the triangle is x degree.

Now according to the question the angles are in ration 1:2:1.

Hence clearly the angles are x, 2x and x

Now we know that the sum of angles of any triangle is equal to 180 degree.

so clearly  x + 2x  + x = 180

hence x = 45 '

So the angles of triangle are listed below 45',  90',  45'

Hope it helps.