Answer:
13. x = 7 ; Converse : Alternate interior angles are equal .
14. x=12; Converse used : Linear pair
15. x = 23; Converse: Corresponding angles are equal
Step-by-step explanation:
13.
Refer the attached figure
Given: q || r
(Alternate interior angles )
So, 15x+3=108
15x=108-3
15x=105
x=7
So, x = 7 ; Converse : Alternate interior angles are equal .
14.
Refer the attached figure
Given q||r
(Alternate interior angles
So,
Now(Linear pair)
So,7x-8+11x-28=180
18x-36= 180
18x=216
x=12
So, x=12; Converse used : Linear pair
15.
Refer the attached figure
Given q||r
(corresponding angles)
90+2x=5x+21
90-21=5x-2x
69=3x
23=x
So, x = 23; Converse: Corresponding angles are equal