Answer:
The correct answer is last option. 103
Step-by-step explanation:
Points to remember
Sum of any two angles of a triangle is equal to the exterior angle of the third angle
To find the measure of <1
It is given that m<2 = 31° and m< 3 = 72°
From the figure we can see that <2 and <3 are two angles of a triangle. And <1 is the exterior angle of third angle of same triangle.
Therefore we can write,
m<2 + m<3 = m<1
m<1 = 31 + 72
= 103°
Therefore the correct answer is last option. 103
