Answer:
Part 1) [tex]m\angle 7=65^o[/tex]
Part 2) [tex]m\angle 4=115^o[/tex]
Part 3) [tex]m\angle 6=115^o[/tex]
Part 4) [tex]m\angle 1=65^o[/tex]
Part 5) [tex]m\angle 16=60^o[/tex]
Part 6) [tex]m\angle 18=60^o[/tex]
Part 7) [tex]m\angle 21=120^o[/tex]
Part 8) [tex]m\angle 10=55^o[/tex]
Part 9) [tex]m\angle 11=125^o[/tex]
Part 10) [tex]m\angle 12=55^o[/tex]
Step-by-step explanation:
Part 1) Find the measure of angle 7
we know that
[tex]m\angle 7=m\angle 3[/tex] ----> by corresponding angles
we have
[tex]m\angle 3=65^o[/tex] ----> given
therefore
[tex]m\angle 7=65^o[/tex]
Part 2) Find the measure of angle 4
we know that
[tex]m\angle 4+m\angle 3=180^o[/tex] ----> by supplementary angles (form a linear pair)
we have
[tex]m\angle 3=65^o[/tex]
substitute
[tex]m\angle 4+65^o=180^o[/tex]
[tex]m\angle 4=180^o-65^o=115^o[/tex]
Part 3) Find the measure of angle 6
we know that
[tex]m\angle 6=m\angle 4[/tex] ----> by alternate exterior angles
we have
[tex]m\angle 4=115^o[/tex]
therefore
[tex]m\angle 6=115^o[/tex]
Part 4) Find the measure of angle 1
we know that
[tex]m\angle 1=m\angle 3[/tex] ----> by vertical angles
we have
[tex]m\angle 3=65^o[/tex]
therefore
[tex]m\angle 1=65^o[/tex]
Part 5) Find the measure of angle 16
we know that
[tex]m\angle 15+m\angle 16=180^o[/tex] ----> by supplementary angles (form a linear pair)
we have
[tex]m\angle 15=120^o[/tex] ---> given
substitute
[tex]120^o+m\angle 16=180^o[/tex]
[tex]m\angle 16=180^o-120^o=60^o[/tex]
Part 6) Find the measure of angle 18
we know that
[tex]m\angle 18=m\angle 16[/tex] ----> by alternate interior angles
we have
[tex]m\angle 16=60^o[/tex]
therefore
[tex]m\angle 18=60^o[/tex]
Part 7) Find the measure of angle 21
we know that
[tex]m\angle 21=m\angle 15[/tex] ----> by alternate exterior angles
we have
[tex]m\angle 15=120^o[/tex]
therefore
[tex]m\angle 21=120^o[/tex]
Part 8) Find the measure of angle 10
step 1
Find the measure of angle 14
we know that
[tex]m\angle 14+m\angle 15=180^o[/tex] ----> by supplementary angles (form a linear pair)
we have
[tex]m\angle 15=120^o[/tex]
substitute
[tex]m\angle 14+120^o=180^o[/tex]
[tex]m\angle 14=180^o-120^o=60^o[/tex]
step 2
we know that
[tex]m\angle 14+m\angle 7+m\angle 12=180^o[/tex] ---> sum of interior angles of a triangle
we have
[tex]m\angle 14=60^o[/tex]
[tex]m\angle 7=65^o[/tex]
substitute
[tex]60^o+65^o+m\angle 12=180^o[/tex]
[tex]m\angle 12=180^o-125^o=55^o[/tex]
step 3
Find the measure of angle 10
we know that
[tex]m\angle 10=m\angle 12[/tex] ----> by vertical angles
we have
[tex]m\angle 12=55^o[/tex]
therefore
[tex]m\angle 10=55^o[/tex]
Part 9) Find the measure of angle 11
we know that
[tex]m\angle 11+m\angle 12=180^o[/tex] ----> by supplementary angles (form a linear pair)
we have
[tex]m\angle 12=55^o[/tex]
substitute
[tex]m\angle 11+55^o=180^o[/tex]
[tex]m\angle 11=180^o-55^o=125^o[/tex]
Part 10) Find the measure of angle 12
see Part 8)
[tex]m\angle 12=55^o[/tex]