Page 109 - TB_6B
P. 109
Activity 1 Exterior Angles of Triangles
Learn how interior and exterior angles of a triangle are related.
In triangle ABC, A
ACD is an exterior angle of
ABC, and m C m ACD= 180 .
m A m B m C = 180 . interior exterior angle
Therefore, angle
m ACD = m A m B. B CD
An exterior angle of a triangle is equal to the sum of the 2 interior
angles that are not adjacent to that exterior angle.
1 . Find the measure of a.
a. b.
30 a
110 a 70 125
c. d.
35 85
a
a 143
98
Learn how interior and exterior angles of a triangle are related.
In triangle ABC, A
ACD is an exterior angle of
ABC, and m C m ACD= 180 .
m A m B m C = 180 . interior exterior angle
Therefore, angle
m ACD = m A m B. B CD
An exterior angle of a triangle is equal to the sum of the 2 interior
angles that are not adjacent to that exterior angle.
1 . Find the measure of a.
a. b.
30 a
110 a 70 125
c. d.
35 85
a
a 143
98
