__Circumscribed Circle__**:**

If a polygon is drawn in a circle so that every corner of the polygon lies on the circle, the polygon is called an **inscribed polygon **and the circle is called the **circumscribed circle**. In the figure, is the **center** of the polygon and is the **radius** of the circumscribed circle and id denoted by .

__Inscribed Circle__**:**

If a polygon is drawn outside a circle so that every side of the polygon touches the circle, the polygon is called the **circumscribed polygon **and the circle is called the **inscribed circle**. In the figure, is the radius of the inscribed and is denoted by .

If the polygon is regular then the center of the circle is called is also the center of the polygon.