STEP 1: find base area $ B $
To find base area $ B $ use formula:
$$ B = a^2 $$After substituting $ a = 16 $ we have:
$$ B = 16^2 $$ $$ B = 256 $$STEP 2: find lateral surface $ L $
To find lateral surface $ L $ use formula:
$$ L = 2 \cdot a \cdot s $$After substituting $ a = 16 $ and $ s = 12 $ we have:
$$ L = 32 \cdot 12 $$$$ L = 384 $$STEP 3: find total surface $ A $
To find total surface $ A $ use formula:
$$ A = B + L $$After substituting $ B = 256 $ and $ L = 384 $ we have:
$$ A = 256 + 384 $$ $$ A = 256 + 384 $$ $$ A = 640 $$