Answer:
[tex]BC = 84[/tex]
Step-by-step explanation:
Given
See attachment
Required
Find BC
The sum of [tex]angles\ at\ a\ point[/tex] is 360.
So:
[tex]7n + 12 + 13n - 16 + 6n = 360[/tex]
Collect like terms
[tex]7n + 13n + 6n = 360 + 16 - 12[/tex]
[tex]26n = 364[/tex]
Solve for n
[tex]n = 364/26[/tex]
[tex]n = 14[/tex]
From the circle:
[tex]BC = 6n[/tex]
Substitute 14 for n
[tex]BC = 6*14[/tex]
[tex]BC = 84[/tex]