Geometry is the branch of mathematics concerned with shapes and spaces. It studies points, lines, planes, angles, and other geometric objects and relationships between them. Key concepts in geometry include lines, rays, line segments, planes, parallel and intersecting lines, perpendicular lines, angles, and the different types of angles such as right, acute, obtuse, and straight angles. A geometer is a mathematician who works in the field of geometry.

2.  Geometry (.; geo means earth and metria "measurement")
is a branch of mathematics concerned with questions of
shape, size, relative position of figures, and the properties
of space. A mathematician who works in the field of
geometry is called a geometer.

3. GeometryGeometry
 Point
 Line
 Line segment
 Ray
 Plane
 Parallel lines
 Intersecting lines
 Perpendicular lines
 Angles

4. PointPoint
 An exact location in space. It has no length, no breadth
and no height. It has position and location but
no magnitudes.

5. LineLine
 An endless collection of points along a straight path. The
word ‘line’ usually refers to a ‘straight line’. A line has no
width. It has length only. It is absolutely straight and can
extend indefinitely in both directions.

6. Line segmentLine segment
 Part of a line that has two endpoints. The part of a line
with two definite end points is called line segment

7. RayRay
Part of a line that has one endpoint and extends
endlessly in the other direction

8. PlanePlane
An endless, flat surface that is named by more than two
points not on the same line.

9. Parallel LinesParallel Lines
 Lines do not intersect but are in the same plane . Lines
are parallel if they lie in the same plane, and are the
same distance apart over their entire length

10. Intersecting LinesIntersecting Lines
 Lines meet at one point. Two lines are called
intersecting lines if they have a common point
the common point is called the point of intersection.

11.  Lines form a right angle. A line is perpendicular to
another if it meets or crosses it at right angles (90°).
Perpendicular LinesPerpendicular Lines

12. AnglesAngles
An angle is formed when two rays have the
same endpoint.
This endpoint is called the vertex.
The two rays that form the angle are called
sides.

13.  There are four types of angles
 Right angle
 Straight angle
 Acute angle
 Obtuse angle

14. Right angle
 A right angle is an internal angle which is equal
to 90°.

15. Straight AngleStraight Angle
 If an angle’s measure is 180°, it is called a straight angle.
Straight angles are just lines with three points on them.

16. Acute Angles
 An acute angle is an angle whose measure is less
than 90°. For these kinds of angles, a square could not
fit perfectly at the intersection of the two lines that form
them.

17. Obtuse Angles
 An Obtuse Angle is more than 90° but less than 180°

18. ReviewReview
Name each pictureName each picture
 Ray
 Parallel lines
 Line
1.
2.
3.

19. ReviewReview
Name each pictureName each picture
 Acute angle
 Line segment
 Point
5.

20. ReviewReview
Name each pictureName each picture
 Intersecting lines
 Perpendicular and
Intersecting lines
 Plane