Question

$\displaystyle\huge\green{\underline{\underline{QUESTION}}}$

The radii of the ends of frustum of a cone 45 cm high are 28 cm and 7 cm. Find its volume, the curved surface area and the total surface area?​

Answer 1

Answer:

hii I think that it helps you

Answer 2

Answer:

Let 'ℓ' & R be the radii of the bottom and top circular ends of a frustum of a cone, respectively and 'h' be height of cone.

Volume of the frustum of the cone =  

3

1

​  

×  

7

22

​  

×45(28  

2

+7  

2

+28×7)cm  

3

 

=  

7

22

​  

×15(784+49+196)cm  

3

 

=  

7

22

​  

×15×1029cm  

3

=22×15×147cm  

3

 

=330×147cm  

3

 

Now, l=  

h  

2

+(R−r  

2

)

​  

=  

(45)  

2

+(28−7)  

2

 

​  

=  

2025+441

​  

=  

2466

​  

 

=  

2466

​  

=49.65cm

curved surface area of the frustum of the cone  

=π(R+r)ℓ=[  

7

22

​  

∗(28+7)∗49.65]cm  

2

 

=[22×5×49.65]cm  

2

 

5461.5cm  

2

 

total surface area of frustum of the cone  

π(R+r)ℓ+πR  

2

+πr  

2

 

=[5461.5+  

7

22

​  

×(28)  

2

+  

7

22

​  

×(7)  

2

]cm  

2

 

=[5261.5+  

7

22

​  

×(28)  

2

+(7)  

2

]cm  

2

 

=[5461.5+22×1+9]cm  

2

 

=8079.5cm  

2

 

Step-by-step explanation:

hope it helps you ! and why did you first inbox and then blocked me dear ?