STEP 1: find base area $ B $
To find base area $ B $ use formula:
$$ B = a^2 $$After substituting $ a = 20 $ we have:
$$ B = 20^2 $$ $$ B = 400 $$STEP 2: find lateral surface $ L $
To find lateral surface $ L $ use formula:
$$ L = 2 \cdot a \cdot s $$After substituting $ a = 20 $ and $ s = 32 $ we have:
$$ L = 40 \cdot 32 $$$$ L = 1280 $$STEP 3: find total surface $ A $
To find total surface $ A $ use formula:
$$ A = B + L $$After substituting $ B = 400 $ and $ L = 1280 $ we have:
$$ A = 400 + 1280 $$ $$ A = 400 + 1280 $$ $$ A = 1680 $$