What is bc ? enter your answer in the box. 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.