Question

The csa of a cone is 550 cm square and it's tsa is704cm square. Find its radius

Answer 1

$\blue{\bold{\underline{\underline{Answer:}}}}$

$\green{\tt{\therefore{Radius\:of\:cone=7\:cm}}}$

$\orange{\bold{\underline{\underline{Step-by-step\:explanation:}}}}$

$\green{\underline \bold{Given :}} \\ \tt: \implies C.S.A\: of \: cone =550\:cm^{2}\\ \\ \tt: \implies T.S.A \: of \: cone =704 \: cm^{2} \\ \\ \red{\underline \bold{To \: Find:}} \\ \tt: \implies Radius \: of \:cone =?$

• According to given question :

$\bold{As \: we \: know \: that} \\ \tt: \implies C.S.A \: of \: cone = \pi rl \\ \\ \tt: \implies 550 =\pi rl-----(1)\\\\ \bold{As \: we \: know \: that} \\ \tt: \implies T.S.A \: of \: cone =\pi rl+\pi r^{2} \\ \\ \tt: \implies 704 = 550+\pi r^{2} \\ \\ \tt: \implies 704-550 =\pi r^{2}$

$\tt: \implies 154 = \frac{22}{7} \times {r}^{2} \\ \\ \tt: \implies \frac{154 \times 7}{22} = {r}^{2} \\ \\ \tt: \implies 49 = {r}^{2} \\ \\ \tt: \implies r = \sqrt{49} \\ \\ \green{\tt: \implies r = 7 \: cm}$

Answer 2

$\tt{\huge{\orange{Hello!!!}}} B.Q.$

QUESTION :

The csa of a cone is 550 cm square and it's tsa is704cm square. Find its radius.

GIVEN :

CSA of cone is equal to 550 square cm.

TSA of cone is equal to 704 square cm.

SOLUTION :

CSA of cone = πrl

TSA of cone = πr ( l + r ) = πrl + πr^2

=> 704 = 550 + πr^2

=> πr^2 = 154

=> r^2 = 49

=> r = 7 cm......(A)