This slide is about basic knowledge of lines and circles.

1. CH-BASIC
GEOMETRICAL
IDEAS

2. LINE SEGMENT
A line segment is bounded by two
fixed end points.
LINE
A line has no end point.
RAY
A ray has one starting point
and no end point

3. PARALLEL LINE
A parallel lines can be defined as
two lines in the same plane that
are at equal distance from each
other and never meet.
INTERSECTING LINES
When two or more lines cross each
other in a plane, they are
called intersecting lines.

4. COLLINEAR POINTS
In a given plane, three or
more points that lie on the same
straight line are called collinear
points.
CONCURRENT LINES
When two or more lines pass
through a single point, they
are concurrent with each other
and they are
called concurrent lines.

5. CLOSED FIGURE
A boundary of a closed figure is not
only made of line segments but also by
curves. A shape when starts and ends
at the same point to form a boundary
by line segments or by curves.
OPEN FIGURE
An open shape can be defined as
a shape or figure
whose line segments and/or
curves do not meet. They do not
start and end at the same point.

6. CHORD
The line segment that
connects two points on the
circle but do not pass through
the centre of the circle. DE is
the chord of the circle.
DIAMETER
The line segment that connects
two points on the circle and
passes through the centre of the
circle. It is double the value of
the radius. AB is the diameter of
the circle.
RADIUS
The line segment that
connects the centre of
circle to any point on
the circle.

7. ARC OF CIRCLE
An arc is the part of
circumference.
CIRCUMFRENCE
It is the distance
around the circle.
SEMICIRCLE
A semicircle is formed
when a lining passing
through the centre
touches the two ends on
the circle.