16 Questions
What is the term for a part of a line with two end points?
Line segment
What is the term for points that lie on the same line?
Collinear points
What is the term for the end point of an angle?
Vertex
What type of angle measures between 0° and 90°?
Acute angle
What type of angle is exactly equal to 90°?
Right angle
What type of angle measures between 90° and 180°?
Obtuse angle
What type of angle is equal to 180°?
Straight angle
What type of angle measures between 180° and 360°?
Reflex angle
What is the minimum number of points required to draw a line?
Two
What is the purpose of studying the properties of angles formed between lines?
To understand the properties of plane surfaces in daily life
What is the role of angles in drawing a plan for a multistoried building?
To draw intersecting lines and parallel lines at different angles
What is the purpose of studying the properties of lines and angles in science?
To study the refraction property of light
What is the relevance of angles in making a model of a hut?
To have knowledge of angles formed between the edges of plane surfaces
What is the purpose of using deductive reasoning in this chapter?
To prove some statements
What is the relevance of lines and angles in an architect's work?
To draw intersecting lines and parallel lines at different angles
What is the role of angles in studying the net effect of forces on a body?
To represent forces acting on a body by directed line segments
Study Notes
Introduction to Lines and Angles
- A minimum of two points are required to draw a line.
- In this chapter, properties of angles formed by intersecting lines and intersecting parallel lines will be studied.
Real-Life Applications of Lines and Angles
- Angles are essential in making models using plane surfaces (e.g., making a model of a hut).
- Architects need knowledge of lines and angles to draw building plans.
- Lines and angles are used in science to study properties of light (e.g., refraction).
- Directed line segments are used to study the net effect of forces on a body.
- Angles are used to find the height of a tower or the distance of a ship from a lighthouse.
Basic Terms and Definitions
- A line segment is a part of a line with two end points, denoted by AB.
- A ray is a part of a line with one end point, denoted by AB.
- A line is denoted by AB.
- Collinear points are points that lie on the same line; non-collinear points do not.
- An angle is formed when two rays originate from the same end point (vertex).
- Arms of an angle are the rays that make the angle.
Types of Angles
- Acute angle: measures between 0° and 90°.
- Right angle: exactly 90°.
- Obtuse angle: greater than 90° but less than 180°.
- Straight angle: equal to 180°.
- Reflex angle: greater than 180° but less than 360°.
This chapter explores the properties of angles formed when two lines intersect and when a line intersects parallel lines, and how to use these properties to solve problems.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
