Surface area of a cone

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Areas related to cone are introduced with geogebra sketch.


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:
  1. What is a solid shape ?
  2. Define a cone ?
  3. Give some examples of conical figures.
  4. Name the parts of a cone.
  5. What shape is its base.
  6. After disection can you identify the shapes it is made of ?
  7. Differentiate lateral surface area and total surface area.
  8. What is the formula to find the area of a circle ?
  9. Whatis the circumference of a circle ?
  10. Differentiate between the slant height and vertical height of a cone.
  11. How do we proceed to find the L.S.A. of the cone.
  12. How do we find the total surface area of the cone.
  • Evaluation:
  1. What part of a circle is the lateral surface of a cone ?
  • Question Corner:
  1. What would be the formula to find the surface area of an ice-cream cone.
  2. What is the frustum of a cone.