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 1 of 8.
Sachin.nani3@gmail.com said:
1 decade ago
I could not understand, please explain any body.
Shafi said:
1 decade ago
Since triangle is rotated with a side of 3 hence radius=3, volume=1/3*22/7r^2h.
Vinay vidhani said:
1 decade ago
We know that long side in right angle triangle is hypotenuses OK let 3 is base and 4 is a height then put the formula of volume of cone is 1/3 *pai r*r*h that's all.
Vinay vidhani said:
1 decade ago
But how can we understand that 3 will base ?
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.
Vidhya said:
1 decade ago
If the side of 3cm is rotated, won't it become the height of the cone ?
Ranjan said:
1 decade ago
I can't understand.
Deepika said:
1 decade ago
We know long side is hypotenuse according to question which will be 5cm then height is 4cm & base is 3cm then we extent the 3cm behind 4cm height as a diameter & draw the circle along this & calculate the volume from formula.
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.
Sakshi said:
1 decade ago
If it is rotated about 3 cm. How could radius be 3 cm?
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