Question

• Curved surface area of a cone of radius 4 cm,
is 201 cm2. Find total surface area of the
same cone in terms of t.​

Answer 1

Given:-

C.S.A of cone = 201sq.cm

radius of cone =4cm

To find:-

The total surface area of cone (T.S.A)

A.T.Q

Now by the formula

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

T.S.A of cone =πr(l+r)

Or.

$\boxed{\sf{T.S.A \:of\:cone =\pi r l+\pi r{}^{2}}}$

Now solve

$\sf\implies T.S.A= C.S.A+bottom\: Surface\:area\\ \\ \sf\implies T.S.A= 201+\dfrac{22}{7}\times (4){}^{2}\\ \\ \sf\implies T.S.A=201+\dfrac{22\times 16}{7}\\ \\ \sf\implies T.S.A=\dfrac{201\times 7+ 22\times 16}{7}\\ \\ \sf\implies T.S.A=\dfrac{1407+ 352}{7}\\ \\ \sf\implies T.S.A=\cancel{\dfrac{1759}{7}}\\ \\ \sf\implies T.S.A=251.28cm{}^{2}$

$\sf{\therefore{T.S.A\:of\:cone= 251.28cm{}^{2}}}$

Answer 2

$\huge \underline {\underline{ \mathfrak{ \green{Ans}wer \colon}}}$

____________________________

✯ Given :

• Radius of cone = 4 cm

• C. S. A of cone = 201 cm².

___________________________

✯ To Find :

We have to find the T. S. A of cone.

___________________________

✯ Solution :

We know that,

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

And where as the area of base which is in circle is , πr²

⇒T.S.A = πrl + πr²

⇒T.S.A = 201 + 22/7 * (4)²

⇒T.S.A = 201 + 22/7 * 16

⇒T.S.A = 201 + 352/7

⇒T.S.A = (201*7 + 352)/7

⇒T.S.A = (1407 + 352)/7

⇒T.S.A = 1759/7

⇒T.S.A = 251.2857

➠ Total Surface Area is 251.3 cm²