Step-by-step explanation:
sum of two interior angles is equal one exterior angle....this implies that,
6x + 15x-12 = 19x+2.....make X the subject
6x+15x-19x = 2+12
2x = 14..... divide both sides by 2
x = 7
this implies that, 19x + 2 where x is 7,
= 19(7) +2
=135°
therefore,<MNI = 135°
