Problem Statement
\angle BAC \equal{} 80{}^\circ, \left|AB\right| \equal{} \left|AC\right|, K∈[AB], L∈[AB, \left|AB\right|^{2} \equal{} \left|AK\right|\cdot \left|AL\right|, \left|BL\right| \equal{} \left|BC\right|, \angle KCB \equal{} ?<spanclass=′latex−bold′>(A)</span> 20∘<spanclass=′latex−bold′>(B)</span> 25∘<spanclass=′latex−bold′>(C)</span> 30∘<spanclass=′latex−bold′>(D)</span> 35∘<spanclass=′latex−bold′>(E)</span> 40∘