Question

the ratio of base and height of a cone is 5:12 and volume is 314.29cm².find the csa and tsa.​

Answer 1

$\huge\mathfrak{\color{blue}{\underline{\underline{❥︎ᴀɴꜱᴡᴇʀ}}}}$

Let radius be 4x and height be 3x.

∴ Area of base = πr

2

=154⇒

7

22

×(4x)

2

=154

⇒16x

2

=

22

154×7

⇒x

2

=

16

49

⇒x=

4

7

∴ Radius = 4×

4

7

=7cm,height=3×

4

7

=

4

21

=5.25cm

Now, CSA of cone = πrlandl=

r

2

+h

2

=

49+(5.25)

2

∴ CSA =

7

22

×7×8.75=192.5cm

Answer 2

$\huge\mathfrak{\color{cyan}{\underline{\underline{❥︎ᴀɴꜱᴡᴇʀ}}}}$

Let radius be 4x and height be 3x.

∴ Area of base = πr

2

=154⇒

7

22

×(4x)

2

=154

⇒16x

2

=

22

154×7

⇒x

2

=

16

49

⇒x=

4

7

∴ Radius = 4×

4

7

=7cm,height=3×

4

7

=

4

21

=5.25cm

Now, CSA of cone = πrlandl=

r

2

+h

2

=

49+(5.25)

2

∴ CSA =

7

22

×7×8.75=192.5cm