Edexcel GCSE Foundation Maths: Volume of a Sphere and Cone
What is volume?
Volume is the amount of 3-dimensional space an object takes up. It's measured in cubic units, like cubic centimetres (cm³) or cubic metres (m³).
Volume of a Sphere
A sphere is a perfectly round 3D object.
Formula:
Where:
- V = Volume of the sphere
- ? (pi) ? 3.142
- r = Radius of the sphere
Example:
A sphere has a radius of 5cm. Calculate its volume.
- Substitute the value of r into the formula: V = (4/3)?(5cm)³
- Calculate: V ? (4/3) × 3.142 × 125cm³ ? 523.6cm³
Therefore, the volume of the sphere is approximately 523.6 cm³.
Volume of a Cone
A cone is a 3D object with a circular base and a pointed top.
Formula:
Where:
- V = Volume of the cone
- ? (pi) ? 3.142
- r = Radius of the base of the cone
- h = Height of the cone
Example:
A cone has a radius of 4cm and a height of 6cm. Calculate its volume.
- Substitute the values of r and h into the formula: V = (1/3)?(4cm)²(6cm)
- Calculate: V ? (1/3) × 3.142 × 16cm² × 6cm ? 100.5cm³
Therefore, the volume of the cone is approximately 100.5 cm³.
Key points to remember:
- Always remember to use the correct formula for each shape.
- Make sure to include the correct units in your answer.
- Round your answer to an appropriate degree of accuracy, usually to one or two decimal places.
- Practice using these formulas with different examples to solidify your understanding.