1. Central angel
The angle in a circle whose vertex is
the center of the circle is called the
CENTRAL ANGLE

2. Inscribed angle
• Inscribed angle is defined as the angle formed
by 2 chords that meet at the same point on a
circle

3. chord
• A straight line connecting 2 points on a curve.

4. Area of a circle
• (pie r2) where r=the radius of the circle of pie
=3.141592 a=pi r 2

5. circumference
• The circumference of a circle is the
perimeter—the distance around the outer
edge.

6. radius
• The radius of a circle is the distance from the
center of the circle to the outside edge.

7. diameter
• The diameter of a circle is longest distance
across a circle. (the diameter cuts through the
center of the circle. this is what makes it the
longest distance.)

8. sector
• The area between an arc and two radii of a
circle. Also referred as wedge. The region
enclosed to two and an arc. The two radii
divide the circle into 2 sectors called a major
sector and a minor sector.

9. Standard form
• (x-h) 2+(y-k) 2.the center is at (n,k). The radius
is r

10. Transformation form
• (x-hr)2 +(y-kr)2=1

11. General form
• ax2+by2+cx+1y+e=0

12. Mapping notation
• (x,y)-------------(rx+h,ry+k)
• Center (h,k),radius =r