Question

If the radius of base of a cone is 7 cm and its height is 14 cm, what is its curved
surface area ?​

Answer 1

Answer:

498.35cm

Step-by-step explanation:

Given that,

Height of cone = 14 cm  

Radius of base = 7 cm  

We know that,

Surface area, A=πr(r+  

h  

2

+r  

2

 

​  

)

Substituting the value from (i) & (ii)

A=π(7)(7+(14)  

2

+7  

2

)

=7π(7+  

245

​  

)

=7π(7+15.65)

=7×3.14(7+15.65)

=498.35cm  

2

 

∴  

A=498.35cm  

2

 

​

Answer 2

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Given :-

• Radius of base of cone = 7cm
• Radius of base of cone = 7cm Height of cone = 14cm

To Find :-

• Curved surface area of cone

Solution :-

Radius of base of cone = 7cm

Radius of base of cone = 7cm Height of cone = 14cm

For finding the curved surface area of cone we need to find out the slant height of the cone .

Slant height = $\sqrt{r² + h²}$

= $\sqrt{(7)² + (14)²}$

= $\sqrt{49 + 196}$

= $\sqrt{245}$

= 15.65 cm

Now ,

Curved Surface area of cone = πrl

=> $\dfrac{22}{7}$ × 7 × 15.65

=> 22 × 15.65

=> 344.3 cm²