Răspuns :
Notam masura unghiului cu x
(90-x)/(180-x) = 1/3
3(90-x) = 180-x
270 - 3x = 180-x
270-180 = 3x-x
90 = 2x
x = 90:2
x = 45 grade
(90-x)/(180-x) = 1/3
3(90-x) = 180-x
270 - 3x = 180-x
270-180 = 3x-x
90 = 2x
x = 90:2
x = 45 grade