Aptitude - Volume and Surface Area - Discussion
Discussion Forum : Volume and Surface Area - General Questions (Q.No. 8)
8.
The slant height of a right circular cone is 10 m and its height is 8 m. Find the area of its curved surface.
30
m2
m240 m2
m260 m2
m280 m2
m2Answer: Option
Explanation:
l = 10 m,
h = 8 m.
So, r = l2 - h2 = (10)2 - 82 = 6 m.
Curved surface area = rl = ( x 6 x 10) m2 = 60 m2.
Discussion:
11 comments Page 1 of 2.
Akhil said:
5 years ago
@Mustafa.
It is a right circular cone. So given details are height 8 cm, slant height 10 cm, we need to find the base length ie the radius, which can be obtained Pythagoras theorem.
It is a right circular cone. So given details are height 8 cm, slant height 10 cm, we need to find the base length ie the radius, which can be obtained Pythagoras theorem.
(1)
Ngawang Chojey said:
7 years ago
@Nikita is right.
You can use the formula of a right triangle to derive the length of base i.e. equal to radius: h^2=a^2+b^2.
Where, h=slant height, a=hight of a right triangle and b=base of a right triangle.
You can use the formula of a right triangle to derive the length of base i.e. equal to radius: h^2=a^2+b^2.
Where, h=slant height, a=hight of a right triangle and b=base of a right triangle.
(1)
Nikita said:
8 years ago
L = 10 m.
H = 8 m.
R = (10 * 10) - (8 * 8).
R = 100 - 64 = 36.
Square root of 36 is 6.
= 6 * 10 = 60m.
H = 8 m.
R = (10 * 10) - (8 * 8).
R = 100 - 64 = 36.
Square root of 36 is 6.
= 6 * 10 = 60m.
Mustafa said:
8 years ago
Yeah, 10-8 should be 2 not 6.
(1)
Justin said:
8 years ago
Answer is A, why you are taking as a full height of 10?
We need a radius only,
I think;
(22/7) x 6 x 5,
(22/7) x 30 => is a correct Answer.
We need a radius only,
I think;
(22/7) x 6 x 5,
(22/7) x 30 => is a correct Answer.
(1)
Gowtham said:
9 years ago
@Sunil.
How 10-8 = 6?
It should be 2.
How 10-8 = 6?
It should be 2.
(1)
Krutarth vaidya said:
9 years ago
C is also correct.
L = 10,
H = 8,
So, r = l2 - h2 = (10)2 - 82 = 6 m.
Area = 60 m^2.
L = 10,
H = 8,
So, r = l2 - h2 = (10)2 - 82 = 6 m.
Area = 60 m^2.
Islam said:
9 years ago
C is correct.
l = 10 m,
h = 8 m.
So, r = l2 - h2 = (10)2 - 82 = 6 m.
Curved surface area = rl = ( x 6 x 10) m2 = 60 m2.
l = 10 m,
h = 8 m.
So, r = l2 - h2 = (10)2 - 82 = 6 m.
Curved surface area = rl = ( x 6 x 10) m2 = 60 m2.
Subhasis said:
9 years ago
I think r should be 6/2 = 3.
What is the right answer?
What is the right answer?
Sunil said:
10 years ago
Curved surface area of cone = rl.
r stands for radius.
l stands for slant height.
r = ?
height = 8 m.
l = 10 m.
First we should find to r (radius). Then we can find curved surface area of cone.
r = l - r.
r = 10-8 = 6 m.
Put value of r in given formula.
rl = 6 m*10 m = 60 m^2.
(C) 60 m^2 correct option.
r stands for radius.
l stands for slant height.
r = ?
height = 8 m.
l = 10 m.
First we should find to r (radius). Then we can find curved surface area of cone.
r = l - r.
r = 10-8 = 6 m.
Put value of r in given formula.
rl = 6 m*10 m = 60 m^2.
(C) 60 m^2 correct option.
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