# Find the distance between the point (-3,4,-6)and its image in the XY plane. Pls answer fast..dont give any links..pls give explanation

*x*,

*y*,

*z*) then the image of this point (as reflected by a mirror in the

*xy*plane) has coordinates (

*x*,

*y*, -

*z*).

Hence the coordinate of the image of the point(-3,4,-6) in xy-plane will be (-3,4,6).

So the distance between them will be d = $\sqrt{({\mathrm{x}}_{2}-{\mathrm{x}}_{1}{)}^{2}+({\mathrm{y}}_{2}-{\mathrm{y}}_{1}{)}^{2}+({\mathrm{z}}_{2}-{\mathrm{z}}_{1}{)}^{2}}\phantom{\rule{0ex}{0ex}}=\sqrt{{\left(-3+3\right)}^{2}+{\left(4-4\right)}^{2}+{\left(6+6\right)}^{2}}\phantom{\rule{0ex}{0ex}}=\sqrt{(6+6{)}^{2}}\phantom{\rule{0ex}{0ex}}=12$

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