Question 21
The point $T$ is taken on the edge $AD$ of the regular pyramid $VABCD$, with apex $V$, so that $\frac{AT}{TD} = \frac{1}{4}$, and the straight line $TS$, perpendicular on $VB$, is drawn ($S \in VB$). If the straight lines $TS$ and $AD$ are perpendicular, prove that the height of the pyramid equals the length of the sides of its base.
Gabriel Popa
Gabriel Popa