A solid sphere of radius 3 cm is melted to form a right circular cone...
Given,
Radius of sphere = 3 cm
Height of the cone = Half of the radius of the cone
Volume of Sphere = Volume of Cone
Volume of Sphere
= 4/3 × πR3
Volume of Cone
=1/3 × πr2h
Suppose the height and radius of the cone are ' h ' and ' r ' respectively.
∴ h = r/2
Applying the formula:
43 × π × 3 × 3 × 3 = 1/3 × π × r × r × h
Put
h = r/2
⇒ 4/3 × 3 × 3 × 3 = 1 / 3 × r × r × r/2
⇒ r3 = 216
⇒ r = 6
∴ Radius of the cone =6 cm.
Hence, the correct option is (D).
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A solid sphere of radius 3 cm is melted to form a right circular cone...
To solve this problem, let's break it down into steps:
Step 1: Find the volume of the solid sphere.
The volume of a sphere is given by the formula V = (4/3)πr^3, where r is the radius of the sphere. In this case, the radius of the sphere is 3 cm, so the volume of the sphere is V = (4/3)π(3^3) = (4/3)π(27) = 36π cm³.
Step 2: Find the height of the cone.
According to the given information, the height of the cone is half the radius of the cone. Since the radius of the sphere is 3 cm, the height of the cone is 3/2 = 1.5 cm.
Step 3: Find the volume of the cone.
The volume of a cone is given by the formula V = (1/3)πr^2h, where r is the radius of the base of the cone and h is the height of the cone. In this case, the height of the cone is 1.5 cm, and we need to find the radius of the cone.
Step 4: Substitute the known values into the volume formula of the cone.
We know that the volume of the cone is equal to the volume of the sphere, so we can set up the equation:
(1/3)πr^2(1.5) = 36π
Step 5: Simplify and solve for r.
Dividing both sides of the equation by (1/3)π(1.5), we get:
r^2 = 36/1.5
r^2 = 24
Taking the square root of both sides, we get:
r = √24
r ≈ 4.9 cm
Therefore, the radius of the cone is approximately 4.9 cm, which is closest to option (D) 6 cm.
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