Telpā dots vektors $\stackrel{\to }{\mathit{AB}}$,
$A\left({x}_{1};{y}_{1};{z}_{1}\right)$ - vektora sākumpunkts,
$B\left({x}_{2};{y}_{2};{z}_{2}\right)$ - vektora galapunkts,
tad $\stackrel{\to }{\mathit{AB}}=\left({x}_{2}-{x}_{1};{y}_{2}-{y}_{1};{z}_{2}-{z}_{1}\right)$, un vektora garums $\left|\stackrel{\to }{\mathit{AB}}\right|=\sqrt{{\left({x}_{2}-{x}_{1}\right)}^{2}+{\left({y}_{2}-{y}_{1}\right)}^{2}+{\left({z}_{2}-{z}_{1}\right)}^{2}}$
Dots vektors $\stackrel{\to }{\mathit{KD}}$, $K\left(4;-7;6\right)$ un $D\left(-5;-4;1\right)$.
Aprēķini vektora $\stackrel{\to }{\mathit{KD}}$ garumu.
$\begin{array}{l}\left|\stackrel{\to }{\mathit{KD}}\right|=\sqrt{{\left({x}_{2}-{x}_{1}\right)}^{2}+{\left({y}_{2}-{y}_{1}\right)}^{2}+{\left({z}_{2}-{z}_{1}\right)}^{2}}\\ \left|\stackrel{\to }{\mathit{KD}}\right|=\sqrt{{\left(-5-4\right)}^{2}+{\left(-4-\left(-7\right)\right)}^{2}+{\left(1-6\right)}^{2}}\\ \left|\stackrel{\to }{\mathit{KD}}\right|=\sqrt{{\left(-9\right)}^{2}+{\left(3\right)}^{2}+{\left(-5\right)}^{2}}\\ \left|\stackrel{\to }{\mathit{KD}}\right|=\sqrt{81+9+25}\\ \left|\stackrel{\to }{\mathit{KD}}\right|=\sqrt{115}\end{array}$