Question

the curved surface area of cone is 4070 centimetre square and its diameter is 70 cm what is its slant height ​

Answer 1

$\huge\mathbb{SOLUTION:-}$

$\sf\underline{\blue{\:\:\:\:\:\:\:\: Given:-\:\:\:\:\:\:\:}}$

$\sf\bullet Radius\:of\:cone=\cancel{\dfrac{70}{2}}= 35cm\\ \\ \sf\bullet C.S.A\:of\:cone=4070cm{}^{2}$

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

• where l is the slant height of cone

$\bf\underline{\red{\:\:\:\:\:\:\:\:A.T.Q:-\:\:\:\:\:\:\:}}$

$\sf\implies \pi r l=4070\\ \\ \sf\implies \dfrac{22}{\cancel7}\times \cancel{35}\times l =4070\\ \\ \sf\implies 22\times 5\times l=4070\\ \\ \sf\implies 110\times l=4070\\ \\ \sf\implies l=\cancel{\dfrac{4070}{110}}\\ \\ \sf\implies l=37$

$\boxed{\red{\bf{slant\: height\:of\:cone=37cm}}}$

Answer 2

Step-by-step explanation:

Given that CSA of cone is 4070cm²

Diameter of cone = 70cm

Radius of cone = d/2=70/2=35cm

CSA of cone = πrl

πrl = 4070

22/7*35*l = 4070

22*5 l = 4070

110 l = 4070

l = 4070/110

l = 37 cm