STEP 1: find side $ a $
To find side $ a $ use formula:
After substituting $ B = 64 $ we have:
$$ B = a^2 $$ $$ a^2 = 64 $$ $$ a = \sqrt{ 64 } $$ $$ a = 8 $$STEP 2: find lateral surface $ L $
To find lateral surface $ L $ use formula:
$$ L = 2 \cdot a \cdot s $$After substituting $ a = 8 $ and $ s = 15.3 $ we have:
$$ L = 16 \cdot 15.3 $$$$ L = 244.8 $$