Question #3bfd4

And thus to a first approximation it is $\text{trigonal pyramidal}$.
The experimental $\angle H - P - H = {93.5}^{\circ}$, which is SMALLER than the corresponding angle in ammonia, $\angle H - N - H = {105}^{\circ}$, and hard to rationalize on simple grounds of VESPER. You should buttonhole your prof for his rationale. (And repost his account here!)