Escitalopram is an oral drug that is used for treating depression and generalized anxiety disorder. Chemically, escitalopram is similar to citalopram . Both are in a class of drugs called selective serotonin reuptake inhibitors (SSRIs), a class that also includes fluoxetine , paroxetine and sertraline .
1 A circle is all of the points that are a fixed distance, known as the radius, from a given point, known as the center of the circle. 2  Explore the standard equation of a circle using the applet below (Go here for a larger version).
The centre of a circle is the point in the very middle. The radius of a circle is a line from the centre of the circle to a point on the side. All points on the edge of the circle are at the same distance from the centre. In other words, the radius is the same length all the way around the circle. Mathematicians use the letter r for the length of a circle's radius.