Volume of Sphere with Radius and Formula Examples
Volume of sphere is the space occupied by a spherical solid. It is calculated using the radius and the value of π. This page explains the volume of sphere formula, diameter-based calculations, unit conversions, scaling properties, and solved volume of sphere problems for quantitative aptitude.
What Is the Volume of a Sphere?
The radius is the distance from the centre of the sphere to any point on its surface. Since radius is cubed, the volume is expressed in cubic units. If the diameter d is given, use r = d/2, so V = πd³/6. For a sphere of radius 3 cm, using π = 3.14, V = 4/3 × 3.14 × 3³ = 113.04 cm³.
Volume of Sphere Video Lessons
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Sphere and Hemisphere: Volume and Surface Area
Learn the formulas and methods to calculate the volume and surface area of spheres and hemispheres, including how to apply them to quantitative aptitude problems.
Volume of Sphere Formula & Tricks
Important Formulas
Use this formula when the radius r of the sphere is known.
Use this form when the diameter d is given, because r = d/2.
Use the cube root after rearranging V = 4/3πr³.
This follows from V = πd³/6.
Quick Tricks
When diameter is given, divide it by 2 before applying V = 4/3πr³. Alternatively, use V = πd³/6 directly.
For spheres of the same material, volumes are proportional to the cubes of their radii. Thus, V₁:V₂ = r₁³:r₂³.
If one large sphere is melted into equal smaller spheres without loss of material, the number of smaller spheres equals the ratio of their volumes.
Volume of Sphere Concepts
Using Radius and Diameter
The diameter is twice the radius: d = 2r. Therefore, replacing r by d/2 gives V = 4/3π(d/2)³ = πd³/6. Always keep the length unit unchanged before cubing it.
Effect of Changing the Radius
If the radius changes by a factor k, the volume changes by a factor k³. Doubling the radius makes the volume 8 times larger, while tripling it makes the volume 27 times larger.
Volume Ratio of Two Spheres
The common factor 4π/3 cancels when volumes are compared. If diameters are given instead, the same rule applies because diameter and radius have a constant ratio of 2.
Melted Sphere and Equal Smaller Spheres
The volume of the large sphere equals the total volume of the smaller spheres. Thus, (4/3)πR³ = n(4/3)πr³, giving n = (R/r)³.
Volume of Sphere Visual Guide
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Sphere with Radius Marked
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Volume of Sphere: Quick Revision
Use these formulas and rules for direct calculations and comparison problems.
- Volume of a sphere: V = 4/3πr³.
- Using diameter: V = πd³/6.
- Radius is half the diameter: r = d/2.
- Volume is measured in cubic units such as cm³ or m³.
- If radius changes in the ratio a:b, volume changes in the ratio a³:b³.
- For a melted sphere divided into equal smaller spheres, number = (large radius/small radius)³.
- Use π = 22/7 when the calculation allows exact cancellation; otherwise π = 3.14 may be used as specified.
Volume of Sphere FAQs
What is the volume of sphere formula?
The formula is V = 4/3πr³, where r is the radius. If the diameter d is given, use V = πd³/6.
How do you find the volume of a sphere with diameter 14 cm?
Here r = 7 cm. Therefore, V = 4/3 × 22/7 × 7³ = 4312/3 cm³, or approximately 1437.33 cm³.
What is the volume of a sphere with radius 6 cm using π = 3.14?
V = 4/3 × 3.14 × 6³ = 904.32 cm³.
If the radius of a sphere is doubled, how does its volume change?
The volume becomes 2³ = 8 times the original volume because volume is proportional to the cube of the radius.
What is the volume ratio of spheres whose radii are in the ratio 3:4?
Their volume ratio is 3³:4³ = 27:64.
How many spheres of radius 2 cm can be made by melting a sphere of radius 6 cm?
Number = (6/2)³ = 27 spheres, assuming no material is lost.
