[Pythagorean Theorem (direct and inverse)]

In an isosceles triangle $ABC$, the length of the base $AC$ is $2\sqrt{7}$, and the length of the lateral side is 8. Point $K$ divides the height $BD$ of the triangle in the ratio $2:3$, counting from point $B$. Which is greater: the length of $CK$ or the length of $AC$?
$C K<A C$

$CK < AC$