G. CIRCLE
A circle is a closed curve with all points on the circle at the
same distance from the center point. The major components
of a circle are the diameter, the radius and circumference.
♦ The diameter of the circle is the straight distance from
one outside curved surface through the center point to
the opposite outside curved surface.
♦ The radius of a circle is the distance from the center
point to the outside curved surface. The radius is half the
diameter, and is used to set the compass when drawing
a diameter.
♦ A central angle: is an angle formed by two radial lines
from the center of the circle.
♦ A sector: is the area of a circle lying between two radial
lines and the circumference.
♦ A quadrant: is a sector with a central angle of 90^0 and
usually with one of the radial lines oriented horizontally.
♦ A chord: is any straight line whose opposite ends
terminate on the circumference of the circle.
♦ A segment: is the smaller portion of a circle separated by
a chord.
♦ Concentric circles are two or more circles with a common
center point.
♦ Eccentric circles are two or more circles with out a
common center point.