Mathematics - 3D-Coordinate Geometry Question with Solution | TestHub

The plane containing the z-axis and the normal to the reflecting plane also contains its projected and reflected lines. A normal perpendicular to both directions is (4,3,0).$\begin{array}{c}(4,3,0)\cdot (3,-4,1)=0,\\ \Pi :4x+3y=0.\\ d=\frac{|4(1)+3(2)|}{\sqrt{4^2+3^2}}\\ =\frac{10}{5}=2.\end{array}$