1. Circles Presented by: Desiree Smith, Lauren Rudebush, Justin Dilmore

2. A circle is a round plane figure whose boundary consists of points equidistant from a fixed points. C enter of circle is the central point where radii form a locus of points called a circle. Special Segments in a Circle Radius is a segment with endpoints at the center and on the circle. A chord is a segment with endpoints on the circle. A diameter of a circle is a chord that passes through the center and is made up of collinear radii.

3. Congruent & Concentric Circles Congruent Have the same radius Concentric Have the same center point

4. Great Circles Great circles divide a sphere into two equal halves.

5. Inscribed & Circumscribed Inscribed Drawing a circle in a triangle Circumscribed Using a circle to draw a triangle

6. Area & Circumference ● Area is the number of square units you need to cover a surface. ● Circumference is the distance one would travel in going around a closed shape figure once. A circumference of a circle is a rather useful quantity, and it depends very simply on the radius of the circle

7. Arcs ● An arc is the portion of a circle defined by two endpoints. ● there are a few kind of arcs ○ Minor arc which is the shortest arc connecting two endpoints on a circle. ○ Major arc which is the longest arc connecting two endpoints on a circle. ○ Semicircle which is an arc endpoints that lie on a diameter. ○ Congruent arc which are arcs in the same circle with the same measure. ○ adjacent arcs which have exactly one point in common ● The arc length which is the distance between the endpoints alonf an arc measured in linear units

8. Semicircles A semicircle is an arc whose endpoints are equal to the central point (basically half of a circle)

9. Central Angles A central angle of a circle is an angle with a vertex in the center of a circle. Its sides contain two radii of the circle. The sum of the measures of the central angles of a circle with no interior points in common is 360. Ex: m ∠ 1 + m ∠ 2 + m ∠ 3 = 360