Why? First you need to find out what the angle is for the corner to the left of angle 1 to do so
180-135 which equals 45
then to find on you take 180 (the sun of all interior angles in a triangle equal 180) and subtract all the angles give... 180-21-45= 114 (which makes since because angle one is obtuse and so is it) Now for angle to you need to find the corner that is next to angle 1 to do so you do...
180-114 (because angle equals 114) this equals 66
Then you do 180-66-80 to get angle 2 which equals 34
