"Representation of Angles" PPT Courseware 2

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"Representation of Angles" PPT Courseware 2

An angle is a figure composed of two rays with common endpoints.

1. Definition of angle:

A figure composed of two rays with common endpoints is called an angle

An angle can also be viewed as a figure formed by a ray rotating around an endpoint.

2. Definition of angle 2:

An angle can also be viewed as a figure formed by a ray rotating around its endpoint.

The ray at the starting position is called the starting side of the angle,

The ray at the ending position is called the terminal side of the angle.

There are four ways to represent angles:

(1) Use three capital letters to represent the angle;

(2) Use a capital English letter to represent the angle;

(3) Use an Arabic numeral to represent the angle;

(4) Use a Greek letter to represent the angle.

Exercise 1

Among the following four figures, the figure that can use ∠1, ∠AOB, and ∠O to represent the same angle is ( ).

Exercise 2

Please express the angles in the figure in different ways and fill in the following table:

Exercise 3

As shown in the figure, three capital letters are used to represent the angles,

∠1 is ∠AEC, ∠2 is ∠BED,

∠3 is ∠ABC, ∠4 is ∠BCE.

summary

⒈An angle is a figure composed of two rays with common endpoints. The elements of the angle are vertices and sides. The size of the angle does not change with the length of the side, that is, it has nothing to do with the side.

⒉ There are four ways to represent angles: ① It can be represented by three capital letters; ② It can be represented by a number; ③ It can also be represented by a Greek letter; ④ It can be represented by one capital letter.

In particular, a capital letter must be used to avoid confusion.

On-site inspection:

1. In Figure 1, ∠α and ∠β can be represented by letters A, B, and C as _______ and _______ respectively.

2. In Figure 2, how many angles are there with B as the vertex? Express them. How many angles are there with D as the vertex? Express them.

Answer: There are three angles with B as the vertex, namely ∠ABD, ∠DBC, and ∠ABC; there are four angles with D as the vertex, namely ∠ADE, ∠ADB, ∠BDC, and ∠CDE.

The concept of angle

1. An angle is a figure composed of two rays with common endpoints.

2. An angle can also be regarded as a figure composed of a ray rotating around the endpoint.

Which of the following statements is correct ( )

(A) Two rays with a common point are called angles

(B) Both sides of a right angle form a straight line

(C) The ray is a circumferential angle

(D) The figure formed by two line segments drawn from a point is called an angle.

True or false:

(1) The figure formed by two rays is called an angle;

(2) The angle is formed by rotating a ray;

Which of the following expressions of diagonal angles is incorrectly understood ( )

(A) An angle can be represented by three capital letters, with the vertex letter written in the middle and the points on each side written on both sides.

(B) Any angle can be represented by a vertex letter

(C) When expressing an angle, sometimes an arc can be added close to the vertex and numbers can be added to indicate it.

(D) When representing an angle, an arc can sometimes be added close to the vertex and marked with a Greek letter.

Decide whether the following statement is correct or not:

(a) ∠1 is ∠A;

(b) ∠2 is ∠B;

(c) ∠3 is ∠C.

explore

If there are no rays in ∠AOB, then there are _______ angles in the figure.

If there is 1 ray in ∠AOB, then there are _______ angles in the figure.

If there are 2 rays in ∠AOB, then there are _______ angles in the figure.

If there are 10 rays in ∠AOB, then there are _______ corners in the figure.

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"Representation of Angles" PPT courseware 3:

"Representation of Angles" PPT Courseware 3 Learning Objectives 1. Understand the definition of angles and related concepts. 2. Understand concepts such as angles, right angles, square angles, and circumferential angles from the perspective of motion. 3. Master the expression of angles. Definition of angle 1: An angle is formed by two rays with common endpoints..

"Representation of Angles" PPT courseware:

"Representation of Angle" PPT courseware Definition of Angle (1) An angle is a figure composed of two rays with common endpoints. Definition of Angle (2) The ray at the starting position is called the starting side of the angle, and the ray at the ending position, It is called the terminal side of an angle. When the initial and terminal sides of an angle are exactly...

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Update Time: 2024-10-02

This template belongs to Mathematics courseware Qingdao Edition Seventh Grade Mathematics Volume 2 industry PPT template

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