# Trigonometry

posted by
**Shin**
.

Γ is the circumcircle of triangle ABC with radius 12√2. If 9cos(∠B+∠C)cos∠A=−1, what is the value of BC?

posted by
**Shin**
.

Γ is the circumcircle of triangle ABC with radius 12√2. If 9cos(∠B+∠C)cos∠A=−1, what is the value of BC?