Aptitude - Volume and Surface Area - Discussion

Discussion Forum : Volume and Surface Area - General Questions (Q.No. 1)

Volume and Surface Area

A right triangle with sides 3 cm, 4 cm and 5 cm is rotated the side of 3 cm to form a cone. The volume of the cone so formed is:

cm³

Answer: Option

Explanation:

Clearly, we have r = 3 cm and h = 4 cm.

Volume =	1	r²h =		1	x x 3² x 4	cm³	= 12 cm³.
	3			3

Discussion:

77 comments Page 4 of 8.

Anonymous said: 1 decade ago

Is the cone with base 3 rotated (form imaginary cone shape) or is it folding it (say paper) to form cone? if so how its r=3?

D Priya said: 8 years ago

A cone can be rotated and formed from a triangle by considering the base. Rotate the 4cm angle to the base and proceed.

Shivam Ahuja said: 6 years ago

I think the answer may be 16π as per question, it does not tell us about along which axis we have to rotate it.

(1)

Tina said: 10 years ago

If 3 cm side is rotated, shouldn't it form circumference of cone?

Then 2*pie*r = 3.

How can r itself be 3 here?

Josh said: 1 decade ago

We take orderly the sides of triangle in required it is simply to calculate using formula 1/3*3.14*r^2*h.

Sravanthi said: 10 years ago

It is not mentioned that 3 is base and 4 is height. Why can't 3 be height and 4 be base? please explain.

Nameera khan said: 1 decade ago

How can we know the height is 4 its not given even it can be 5 also did not understand please explain?

Kanwar Pal Singh said: 1 decade ago

@Swati.

I think you are solving with value of "pi". Otherwise the calculation shit is so simple.

Kaushal said: 8 years ago

Rotated about side 3 means,
height = 3,
base radius = 4,

So area 1/3* π * 16 * 3 = 16 π.

Rama said: 10 years ago

Since triangle is rotated with side of 3 cm hence radius is 3.

Clearly, we have v-1/3*r*r*h.

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