Its fillet is 360 degrees. So angle 3 is 90 degrees. The sum of the internal angles of a triangle is 180. So the sum of one angle and two angles is 180-90=90. So angle two and angle one are 45 degrees. Angle 3 = 360-270 = 90 degrees 1 = angle 2 = (180-90)/2 = 45 degrees.