Surface area of a cone
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Areas related to cone are introduced with geogebra sketch.
Objectives
Understand surface area
To calculate surface area of a cone
Estimated Time
40 minutes.
Prerequisites/Instructions, prior preparations, if any
Basics about cone, circle and pythogoras theorm should have been covered.
Materials/ Resources needed
Digital: Laptop, geogebra file, projector and a pointer.
Geogebra file: Sector of a Cone , Surface area of a cone
Download this geogebra file from this link.
Download this geogebra file from this link.
Process (How to do the activity)
The teacher after initial discussion on a cone and its properties can project the geogebra file and enable the understanding of derivation of formulae for surface area of a cone.
- Developmental Questions:
- What is a solid shape ?
- Define a cone ?
- Give some examples of conical figures.
- Name the parts of a cone.
- What shape is its base.
- After disection can you identify the shapes it is made of ?
- Differentiate lateral surface area and total surface area.
- What is the formula to find the area of a circle ?
- Whatis the circumference of a circle ?
- Differentiate between the slant height and vertical height of a cone.
- How do we proceed to find the L.S.A. of the cone.
- How do we find the total surface area of the cone.
- Evaluation:
- What part of a circle is the lateral surface of a cone ?
- Question Corner:
- What would be the formula to find the surface area of an ice-cream cone.
- What is the frustum of a cone.