Respuesta :

Answer:

A

Step-by-step explanation:

angle 3 and 4 make a 180° angle

so angle 3 = 180 - 81 = 99°

because sum of 3 angle in 1 triangle equal 180°

angle 2 = 180 - angle 3 - angle 1

angle 2 = 180 - 99° -42° = 39°

DONE :))

Answer:

a. 39°

Step-by-step explanation:

The sun of two interior angles' measure in a triangle is equal to an exterior angle that is not neighbouring them.

Therefore m<1 + m<2 = m<4

if 42° + m<2 = 81° then m<2 = 81° - 42° ➡ m<2= 39°