Based on VSEPR theory, the number of 90 degree $\mathrm{F}-\mathrm{Br}-\mathrm{F}$ angles in $\mathrm{BrF}_5$ is

In $\mathrm{BrF}_5$ number of electrons $=6$ $(1 l p+5 b p)$ So, the structure is supposed to be square pyramidal but will be distorted because of additional lp- $b p$ interaction.
Additional $\quad l p-b p$ interaction reduces the all bond angle and do not let any angle to be $90^{\circ}$. Chemical bonding Conceptual IV