STEP 1: find base area $ B $
To find base area $ B $ use formula:
$$ B = a^2 $$After substituting $a = 3.46\, \text{cm}$ we have:
$$ B = \left( 3.46\, \text{cm} \right)^{2} $$ $$ B = 11.9716\, \text{cm}^2 $$STEP 2: find lateral surface $ L $
To find lateral surface $ L $ use formula:
$$ L = 2 \cdot a \cdot s $$After substituting $a = 3.46\, \text{cm}$ and $s = 4\, \text{cm}$ we have:
$$ L = 6.92\, \text{cm} \cdot 4\, \text{cm} $$$$ L = 27.68\, \text{cm}^2 $$STEP 3: find total surface $ A $
To find total surface $ A $ use formula:
$$ A = B + L $$After substituting $B = 11.9716\, \text{cm}^2$ and $L = 27.68\, \text{cm}^2$ we have:
$$ A = 11.9716\, \text{cm}^2 + 27.68\, \text{cm}^2 $$ $$ A = 11.9716\, \text{cm}^2 + 27.68\, \text{cm}^2 $$ $$ A = 39.6516\, \text{cm}^2 $$