## Sunday, 17 August, 2008

### Why Learn About Surface Area?

One key topic in geometry is the calculation of surface area for a certain shape.

Why the need for this knowledge? Where is this parameter of Surface Area applied?

Look at the pictures on the right.

Do you see them often? I believe so!

Here, any maker of these items has to know the surface area in order to purchase material to produce them. Geometry calculation in this aspect becomes important for him.

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How does he determine the surface area for the cone?

Given the dimensional specification of the cone, he can spread it out as shown in the diagram on the right.

The spread-out surface area of the desired cone consists of 2 pieces:-
- A base that is a complete circle
- A sector of a larger circle that forms the side of the same cone.

Why spread out the 3-dimensional object into its flat surface (2-dimensional view)?

Advantages are that the ease of computation become apparent and all surfaces to be calculated will be exposed, reducing the chance of missing any surfaces of the object.