<1 and <3 are remote interior angles of <5.
<1 and <2 are remote interior angles of <6.
<2 and <3 are remote interior angles of <4.
What is the relationship between exterior and interior angles of a triangle?
The exterior angle of a triangle is equal to the sum of the measures of the two opposite interior angles in the triangle, that is, exterior angles = sum of opposite interior angles.
For instance, if angle 1 = 60°, and angle 2 = 45°. What is angle 6
Angle 6 = 180° - Angle 3 (supplementary angles)
Angle 3 = 180° - (Angle 1 + Angle 2) sum of angles in a triangle
= 180° - (60° + 45°)
= 180 - 105
Angle 3 = 75°
So,
Angle 6 = 180° - Angle 3
= 180° - 75°
= 105°
Therefore,
Angle 6 = Angle 1 + Angle 2
105° = 60° + 45°
105° = 105°