1 Answer

Saniya · Answer 1 · 2022-08-16T03:42:30+0000

Answer:

A.

$SA= (2)/(3) \pi rl+16 \pi r^2$

Explanation:

Surface area of the original cone

$SA= \pi r l + \pi r^2... (1)$

When, radius is quadrupled and slant height is reduced to one sixth

$i. e. \: \:r = 4r\: \: \&\:\: l= (1)/(6)l$

Plug the above values of r and
in equation (1), new surface area becomes:

$SA= \pi (4r)* (1)/(6) l+ \pi (4r)^2$

$SA= (4)/(6) \pi rl+16 \pi r^2$

$\huge \purple {\boxed {SA= (2)/(3) \pi rl+16 \pi r^2}}$

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