STEP 1: find side $ a $
To find side $ a $ use formula:
$$ A = \dfrac{ \sqrt{ 3 } \cdot a^2 }{ 4 }$$After substituting $A = 4 \sqrt{ 3 }\, \text{cm}$ we have:
$$ 4 \sqrt{ 3 }\, \text{cm} = \dfrac{ \sqrt{ 3 } \cdot a^2 }{ 4 }$$ $$ 4 \sqrt{ 3 }\, \text{cm} \cdot 4 = \sqrt{ 3 } \cdot a^2 $$ $$ 16 \sqrt{ 3 }\, \text{cm} = \sqrt{ 3 } \cdot a^2 $$ $$ a^2 = \dfrac{ 16 \sqrt{ 3 }\, \text{cm} }{ \sqrt{ 3 } } $$ $$ a^2 = 16\, \text{cm} $$ $$ a = \sqrt{ 16\, \text{cm} } $$ $$ a = 4 $$STEP 2: find perimeter $ P $
To find perimeter $ P $ use formula:
$$ P = 3 \cdot a $$After substituting $a = 4\, \text{cm}^0$ we have:
$$ P = 3 \cdot 4 $$ $$ P = 12 $$