# What is the significance of the dashed bonds in this ball-and-stick model?

Of course we cannot depict a three-dimensional tetrahedron on two dimensional paper. When we draw a stereocentre $C {R}_{1} {R}_{2} {R}_{3} {R}_{4}$, two of the $C - R$ bonds are presumed to lie in the plane of the page, and in this scenario one of the $C - R$ bonds projects out of the page, and the remaining $C - R$ bond projects into the page.