STEP 1: find base area $ B $
To find base area $ B $ use formula:
$$ B = a^2 $$After substituting $ a = 0.5 $ we have:
$$ B = 0.5^2 $$ $$ B = 0.25 $$STEP 2: find lateral surface $ L $
To find lateral surface $ L $ use formula:
$$ L = 2 \cdot a \cdot s $$After substituting $ a = 0.5 $ and $ s = 1.9 $ we have:
$$ L = 1 \cdot 1.9 $$$$ L = 1.9 $$STEP 3: find total surface $ A $
To find total surface $ A $ use formula:
$$ A = B + L $$After substituting $ B = 0.25 $ and $ L = 1.9 $ we have:
$$ A = 0.25 + 1.9 $$ $$ A = 0.25 + 1.9 $$ $$ A = 2.15 $$