Question 19
Triangle $ABC$ is an isosceles triangle with $\overline{AB}=\overline{BC}.$ Point $D$ is the midpoint of both $\overline{BC}$ and $\overline{AE},$ and $\overline{CE}$ is $11$ units long. Triangle $ABD$ is congruent to triangle $ECD.$ What is the length of $\overline{BD}?$
