Yes, but how is it geometrically?

If ${ z }_{ 1 }=10i,\quad { z }_{ 2 }=11+12i,\quad { z }_{ 3 }=x$ where $x$ is a real number, then what must be the value of $x$ for $\left| { z }_{ 2 }-{ z }_{ 3 } \right| +\left| { z }_{ 1 }-{ z }_{ 3 } \right|$ to be at its minimum value?

[..This question is not original..]