STEP 1: find angle $ \alpha $
To find angle $ \alpha $ use formula:
$$ \alpha + \beta = 90^o $$After substituting $ \beta = 30^o $ we have:
$$ \alpha + 30^o = 90^o $$ $$ \alpha = 90^o - 30^o $$ $$ \alpha = 60^o $$STEP 2: find height $ h $
To find height $ h $ use formula:
$$ \sin \left( \frac{ \alpha }{ 2 } \right) = \dfrac{ h }{ d_1 } $$After substituting $\alpha = 60^o$ and $d_1 = 3\, \text{cm}$ we have:
$$ \sin \left( \frac{ 60^o }{ 2 } \right) = \dfrac{ h }{ d_1 } $$ $$ \sin( 30^o ) = \dfrac{ h }{ 3 } $$ $$ \frac{ 1 }{ 2 } = \dfrac{ h }{ 3 } $$$$ h = \frac{ 1 }{ 2 } \cdot 3 $$$$ h = \frac{ 3 }{ 2 } $$STEP 3: find side $ a $
To find side $ a $ use formula:
$$ \sin \left( \alpha \right) = \dfrac{ h }{ a } $$After substituting $\alpha = 60^o$ and $h = \dfrac{ 3 }{ 2 }\, \text{cm}$ we have:
$$ \sin( 60^o ) = \dfrac{ \frac{ 3 }{ 2 }\, \text{cm} }{ a } $$ $$ \frac{\sqrt{ 3 }}{ 2 } = \dfrac{ \frac{ 3 }{ 2 }\, \text{cm} }{ a } $$ $$ a = \dfrac{ \frac{ 3 }{ 2 }\, \text{cm} }{ \frac{\sqrt{ 3 }}{ 2 } } $$ $$ a = \sqrt{ 3 }\, \text{cm} $$STEP 4: find perimeter $ P $
To find perimeter $ P $ use formula:
$$ P = 4 \cdot a $$After substituting $a = \sqrt{ 3 }\, \text{cm}$ we have:
$$ P = 4 \cdot \sqrt{ 3 }\, \text{cm} $$ $$ P = 4 \sqrt{ 3 }\, \text{cm} $$