Question

The slant height and base diametere of a conical tomb are 25 m and 14 m respectively. Find the cost of white washing its curved surface at the rate Rs.21p per 100msquare​

Answer 1

$\huge\mathbb{SOLUTION:-}$

$\boxed{\sf{C.S.A\:of\: cone= \pi rl}}$

• l=slant height=25cm

• Base diameter =14cm

• radius =7cm

$\bf\underline{\red{According\:to\: Question:-}}$

Now the C.S.A of cone

$\sf\implies C.S.A=\frac{22}{\cancel7}\times \cancel{7}\times 25\\ \\ \sf\implies C.S.A=550m{}^{2}$

• Cost of white washing the curved surface area is

• Rs21 per 100 sq .m

Now the cost of 1 sq.m

$\sf\implies 1m{}^{2}=\frac{21}{100}Rs$

$\sf\implies Cost\:of\: White\: washing=\frac{21}{10\cancel0}\times 55\cancel0\\ \\ \sf\implies Cost\:of\:white\: washing=\frac{21\times 55}{10}\\ \\ \sf\implies Cost\:of\: white\: washing=115.5Rs.$

$\boxed{\sf{Cost\:of\:white\: Washing=115.5Rs.}}$