Aptitude - Volume and Surface Area - Discussion
Discussion Forum : Volume and Surface Area - General Questions (Q.No. 1)
1.
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:
12
cm3
cm315 cm3
cm316 cm3
cm320 cm3
cm3Answer: 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 |
Video Explanation: https://youtu.be/Njsid2mVwUY
Discussion:
77 comments Page 3 of 8.
Aashish said:
10 years ago
We can take 4 as base. And according to which volume will be 16*pi or remove 16*pi from the options.
Or we can have only one correct option either 12pi or 16pi.
Or we can have only one correct option either 12pi or 16pi.
Saurav said:
5 years ago
It is not mentioned that the 3cm is the base. The triangle is rotated about an axis that becomes height after the rotation then the answer will be 16pie.
(7)
Shivang said:
9 years ago
The question is incomplete, it is not mentioned that the 3 cm is the base. And if it is then cone thus formed has symmetry about x-axis with height 3cm.
Vikash said:
9 years ago
According to me, the language of the question is wrong. Because if it is rotated by side 3cm, its radius will never be 3cm, if anybody visualizes it?
Pintu said:
1 decade ago
It is not mentioned that it is rotated with 3 cm it can be rotated about 3 cm, then in that case 3cm will be the height and 4 cm will be the radius.
Uday kiran.m said:
1 decade ago
There is no need that the rotated side must be the base. You can rotate around the opposite side of triangle then also you will get the same cone.
Tamil said:
5 years ago
If we rotate 3 cm we can form a cone with height 4 cm and hypotenuses 5cm as per Pythagoras theorem and apply the volume of cone 1/3πr^2h.
(2)
Asim said:
1 decade ago
If the question says the triangle is rotated keeping side of 3 cm fixed then the side of 3cm will be the height and 4 cm will be the radius.
Suhail said:
10 years ago
Dear friend,
As it is moved along the side 3 cm hence this 3 cm will be distributed entire circumference.
So 3 = 2*22/7*r.
r = 3/2Π.
As it is moved along the side 3 cm hence this 3 cm will be distributed entire circumference.
So 3 = 2*22/7*r.
r = 3/2Π.
V!CKY said:
10 years ago
@Sakshi and other who doubt in radius @ read question carefully.
i.e rotated the side of 3 cm to form a cone.
Diameter = 2*Radius.
i.e rotated the side of 3 cm to form a cone.
Diameter = 2*Radius.
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