What is the measurement of < 3 and < 1.
angle 1 is apart of a linear pair.
< 2 is 52°

You can revise: the sum of the two adjacent angles is 180°
and the sum of the measurements of the three corners in a triangle is also 180°
<1= 180°-57°=123°
As <2=52°, so we have <3= 180°-(28°+71°+52°)= 180°-151°=29°
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