Verified answer

[tex]a = 3 \\ \tan( \alpha ) = \frac{a}{b} \\ b = \frac{a}{ \tan( \alpha ) } = \frac{3}{ \tan( \alpha ) } \\ S = ab = 3 \times \frac{3}{ \tan( \alpha ) } = \frac{9}{ \tan( \alpha ) } \\ P = 2(a + b) = 2(3 + \frac{3}{ \tan( \alpha ) } ) = 2 \times \frac{3 \tan( \alpha ) + 3}{ \tan( \alpha ) } = \\ = \frac{6 \tan( \alpha ) + 6 }{ \tan( \alpha ) } [/tex]