Answer:
![\stackrel{\LARGE{\frown}}{BC} = 131](https://img.qammunity.org/2022/formulas/geography/high-school/u24izrtayv3ste93o32jvqgwstscsizda9.png)
Step-by-step explanation:
Given
See attachment
Required
Find
![\stackrel{\LARGE{\frown}}{BC}](https://img.qammunity.org/2022/formulas/geography/high-school/ytto98ne40m3wlqh103u0ixkz37wipdgas.png)
First, we need to determine the value of y. This is calculated as:
--- angles in a circle
Collect like terms
![4y + 7y+20y = -6 + 7 + 11+360](https://img.qammunity.org/2022/formulas/geography/high-school/911x56tx6vl4uwcp4yv8k9s9452yllc8zx.png)
![31y = 372](https://img.qammunity.org/2022/formulas/geography/high-school/j0ckwckqv5m0kjlrd8dc92xtbg83h3oxp1.png)
Solve for y
![y = 372/31](https://img.qammunity.org/2022/formulas/geography/high-school/az6ogqjktid2kosz6bawm6l0el8el9monv.png)
![y = 12](https://img.qammunity.org/2022/formulas/history/college/mf3vibeg0oimz5d1hd3i0o8pjmqbfg8ess.png)
The measure of
is calculated as:
![\stackrel{\LARGE{\frown}}{BC} = \stackrel{\LARGE{\frown}}{BA} + \stackrel{\LARGE{\frown}}{AC}](https://img.qammunity.org/2022/formulas/geography/high-school/9g1saohssdltjbciz9knsqpx3t8kookljs.png)
![\stackrel{\LARGE{\frown}}{BC} = 4y + 6 + 7y - 7](https://img.qammunity.org/2022/formulas/geography/high-school/leztu2hcpok0yok5x6ccxthedibv882qob.png)
Collect like terms
![\stackrel{\LARGE{\frown}}{BC} = 4y + 7y + 6 - 7](https://img.qammunity.org/2022/formulas/geography/high-school/khwkrr7pkimw5czocy2h878hn1nx7h9mgl.png)
![\stackrel{\LARGE{\frown}}{BC} = 11y -1\\](https://img.qammunity.org/2022/formulas/geography/high-school/hsx62qam75p9lbo3lu1la9ov518yfylmfi.png)
Substitute
![y = 12](https://img.qammunity.org/2022/formulas/history/college/mf3vibeg0oimz5d1hd3i0o8pjmqbfg8ess.png)
![\stackrel{\LARGE{\frown}}{BC} = 11*12 -1](https://img.qammunity.org/2022/formulas/geography/high-school/3arn427bkwjezbvnmxt09ij567t0z85hhl.png)
![\stackrel{\LARGE{\frown}}{BC} = 131](https://img.qammunity.org/2022/formulas/geography/high-school/u24izrtayv3ste93o32jvqgwstscsizda9.png)