STEP 1: find base area $ AB $
To find base area $ AB $ use formula:
$$ AB = r^2 \cdot \pi $$After substituting $r = 8\, \text{cm}$ we have:
$$ AB = \left( 8\, \text{cm} \right)^{2} \cdot \pi $$ $$ AB = 64\, \text{cm}^2 \cdot \pi $$STEP 2: find lateral area $ AL $
To find lateral area $ AL $ use formula:
$$ AL = 2 \cdot h \cdot r \cdot \pi $$After substituting $r = 8\, \text{cm}$ and $h = 12\, \text{cm}$ we have:
$$ AL = 24\, \text{cm} \cdot 8\, \text{cm} \cdot \pi $$$$ AL = 192\pi\, \text{cm}^2 $$STEP 3: find area $ A $
To find area $ A $ use formula:
$$ A = 2 AB + AL $$After substituting $AB = 64\pi\, \text{cm}^2$ and $AL = 192\pi\, \text{cm}^2$ we have:
$$ A = 2 \cdot 64\pi\, \text{cm}^2 + 192\pi\, \text{cm}^2 $$ $$ A = 128\pi\, \text{cm}^2 + 192\pi\, \text{cm}^2 $$ $$ A = 320\pi\, \text{cm}^2 $$