Question

Find the measure of <1

Answer 1

Consider the triangle (in which angle4 is present)

by angle sum property,

20 + 40 + angle4 = 180

60 + angle4 = 180

angle4 = 180 - 60

angle4 = 120

Also,

angle2 = 120 (vertically opposite angles)

angle1 + angle2 = 180 (linear pair)

angle1 + 120 = 180

angle1 = 180 - 120

angle1 = 60