slove it this question

Answer:
a = 60°
Step-by-step explanation:
Formula used:
[tex] \red{\boxed {\bold {\tan \: \theta = \cot \: (90\degree - \theta)}}} [/tex]
[tex] \tan \: 30 \degree = \cot \: a \\ \cot \: (90 \degree - 30 \degree) = \cot \: a \\ cot \: 60 \degree = \cot \: a \\ 60 \degree = a \\ \huge \red{ \boxed{ a = 60 \degree}}[/tex]