Question

Exercise 14E|
Find the diameter of
1. The curved surface area of a right circular cylinder of height 21 cm is 176 cm square.
Find the diameter of the Base of cylinder
​

Answer 1

Answer:

c.s.a. of cylinder=176cm

h=7cm

r=?

c.s.a. of cylinder =2πrh

2*22/7*r*21=176

176*7/2*22*21=r

1232/924

=1.3333333

=1.33(approx)

r=1.33 cm cubic

diameter =2r

diameter=2*1.33

=2.66cm

Answer 2

Given :

• Height of Cylinder = 21cm.
• C.S.A of Cylinder = 176cm².

To Find :

• Diameter of the base of Cylinder.

Solution :

$\longmapsto\tt{Height=21cm}$

Using Formula :

$\longmapsto\tt{C.S.A\:of\:Cylinder=2\pi{rh}}$

Putting Values :

$\longmapsto\tt{176=2\times\dfrac{22}{\cancel{7}}\times{r}\times{\cancel{21}}}$

$\longmapsto\tt{176=132r}$

$\longmapsto\tt{r=\cancel\dfrac{176}{132}}$

$\longmapsto\tt\bold{r=1.3cm(Approx)}$

Now :

As we know that Diameter is double of Radius.So ,

$\longmapsto\tt{Diameter=2r}$

$\longmapsto\tt{2(1.3)}$

$\longmapsto\tt\bold{2.6cm}$

So , The diameter of the base of Cylinder is 2.6cm..

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• C.S.A of Cylinder = 2πrh
• T.S.A of Cylinder = 2πr(r+h)
• Volume of Cylinder = πr²h

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