Question

8) The radius of a cone is 8 cm and slant height is 10 cm
a) Find the curved surface area of the cone?
b) Find the total surface area of the cone?
c) Find the volume of the cone?​

Answer 1

Answer:

a)220 sq.cm.

b)452.38934cm²

c)402.12386cm³

Step-by-step explanation:

a)r=7cm, l=10cm

C.S.A. of cone =πrl

=

7

22×7×10

=220 sq.cm.

b)A=πrl+πr2=π·8·10+π·82≈452.38934cm²

c)V=πr2h

3

l=r2+h2

Solving forV

V=1

3πr2l2﹣r2=1

3·π·82·102﹣82≈402.12386cm³

Answer 2

Given :-

• The radius of a cone is 8 CM and slant height is 10cm

Solution 1 :-

The radius of the cone = 8cm

Slant height of cone = 10cm

As we know that,

CSA of cone = πrl

Put the required values,

CSA of cone = 22/7 * 8 * 10

CSA of cone = 1760 / 7

CSA of cone = 251.42cm^2

Solution 2 :-

The radius of the cone = 8cm

Slant height of the cone = 10cm

As we know that,

TSA of cone = πr( r + l)

Put the required values,

TSA of cone = 22/7 * 8 ( 8 + 10 )

TSA of cone = 22/7 * 8 * 18

TSA of cone = 3168/7

TSA of cone = 452.57cm^2

Solution 3 :-

The radius of the cone = 8cm

The slant height of the cone = 10cm

As we know that,

Volume of cone = πr^2h/3

Now,

We have to find the Height of the cone

h = √ l^2 - r^2

h = √10^2 - 8^2

h = √ 100 - 64

h = √ 36

h = 6

Now, We have to find volume

Volume of cone = πr^2h/3

Volume of cone = 22/7 * 8 * 8 * 6/3

Volume of cone = 22/7 * 64 * 2

Volume of cone = 2816 /7

Volume of cone = 402.28cm^2

Hence, The volume of the cone is 402.28cm^3$.$