What is BC ? Enter your answer in the box. BC= units An isosceles triangle A B C. Side B C is the base. Vertex A is below base B C. Sides A B and A C are equal. Sides A B and A C are labeled with single tick marks. Side A B is labeled as 8 x minus 4, side A C is labeled as 5 x plus 11, and side B C is labeled as 4 x minus 2.