Respuesta :

jamiexx
the sum of triangle is 180 degrees and therefore here's what I would do, it should be 5 degrees.
Ver imagen jamiexx
Since the sum of all angles of a triangle is 180°
So 100°+4y+25°+3y+20=180°
145°+7y=180°
7y=180°-145°
7y=35°
y=5°