In this tutorial, we are going to learn how to  use Google Reader to subscribe to a blog or website. Before you can do this, first you must have a Google account and second, the website that you are subscribing to must have RSS feeds.  Blogs, pages, or websites with RSS feeds usually have RSS icons (see number 2 below).

Suppose, you like the Mathematics and Multimedia blog and you want to subscribe to its RSS feeds. You should do the following steps:

Figure 1

2. Go to the blog that you want to subscribe to (you’re already here) look for the RSS Feed button and click it.

## Constructing segments with irrational lengths

Since rational numbers can be expressed as fractions (or ratio of two integers), rational numbers can be easily located on the number line using compass and straightedge construction. In principle, a segment of any length can be divided into any number of parts; hence, it is possible to locate any rational number on the number line. Irrational numbers, on the other hand, cannot be expressed as ratio of two integers, so the big question is:

How do we locate irrational numbers on the number line?

The question above is equivalent to: “How do we construct a segment with irrational lengths?”

It is easy to locate some irrational numbers on the number line even with compass and straightedge construction. The irrational $\sqrt{2}$ can be located by constructing square ABCD (Figure 1), getting the diagonal AC, and constructing a circle with radius AC. It follows that the length of AE is $\sqrt{2}$, and the coordinates point E are $(\sqrt{2},0)$.

Figure 1

It is also apparent that the easiest way to construct segments with irrational lengths is by  constructing diagonals of rectangles.  In Figure 2, OB, OC and OD have lengths $\sqrt{2}$, $\sqrt{5}$, and $\sqrt{10}$ respectively. More complicated construction is required to construct other irrational lengths, $\sqrt{3}$ for instance, which is the length of EH. » Read more

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