We start with measurement for spheres. Two important formulae to remember:

Volume of a sphere with radius r is: 4/3 pi r^3

Surface area of a sphere with radius of r is: 4 pi r^2

We then talk about areas of similar figures and volumes of similar solids.

In general, if the ratio of the corresponding lengths of two similar figures is a / b, then the ratio of their areas is ( a / b )^2.

And if the ratio of the corresponding lengths of two similar solids is a / b, then:

• the ratio of their volumes is ( a / b )^3;
• the ratio of their total surface areas is ( a / b )^2.

Knowing the above formulae, as well as the ones we learned last time, allows us to make various calculations in terms of finding the area or volume of some real world objects.

Homework:

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