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CIRCUMFERENCE
AND CIRCLE


Circumference is a line whose points are
equidistant to the center
Circle is a portion of plane or area in a
circumference
THE CIRCUMFERENCE
A circumference is a
closed flat curved
where all its points
are equidistant from
the fixed centre
point
The flat surface
outlined by the
circumference is
called a circle
Elements of a circumference
Diameter. The straight line that goes
through the center of the
circumference and intersect it at two
points
Radius. It is the segment that
connects the center of the
circumference to any other point
Secant. It is a straight line that
intersects a circumference at two
points
Tangent. It is a straight line that
crossed the circumference at only the
point known as tangent point
Arc. It is the fragment of the
circumference between any two points
Arc
Chord. It is the segment that
connects any two points of the
circumference
RADIUS
The radius of a circle
is the distance from
the center of the
circle to the outside
edge.
THE DIAMETER
The diameter of a circle
is the longest distance
across a circle. (The
diameter cuts through
the center of the
circle. This is what makes
it the longest distance.)
PERIMETER OF A CIRCUMFERENCE
The perimeter is the
distance around the outer
edge.
Circumference =
where r = the radius of
the circle
and pi = 3.141592...
A chord of a circle
is a line segment
that connects one
point on the edge of
the circle with
another point on the
circle.
(The diameter is also
a chord: it's just
the longest possible
chord of a circle)
An arc of a circle
is a segment of
the circumference
of the circle.
ANGLES
ANGLE
Two rays that share
the same endpoint
form an angle.
The point where the
rays intersect is
called the vertex of
the angle.
The two rays are
called the sides of
the angle.

We usually specify an angle using Greek
letters like these

α, β, γ
We can also specify an angle with the
letters of its rects adding the symbol
above them : rs
r
α
s
Measuring Angles

We measure the size of an angle using
degrees.
CLASIFICATION
BY
MEASUREMENT
ACUTE < 90º
RIGHT= 90º
OBTUSE > 90º
FLAT = 180º
FULL= 360º
PAIRS OF ANGLES

Complementary
Angles:
Two angles are
called
complementary
angles if the sum of
their degree
measurements are
equals 90 degrees.
b
a
a+b = 90º
ANGLE BISECTOR

An angle bisector is a ray
that divides an angle into
two equal angles.
What kind of shape does have this pizza?
What would it be this portion of pizza in Geometry?