Question

what is the total surface area of a cone whose radius is r/2 and slant height is 2L

Answer 1

R = r/2 , l = 2L

TSA of cone =
$\pi \: r(l + r)$
$\pi \:( r \div 2)(2l \: + r \div 2)$

$\pi(r \div 2)(4l + r) \div 2$
$(\pi \: r {}^{2} 4l) \div 4$


$\pi \: r {}^{2} l$


Thanks