"Parallel Lines" PPT download

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"Parallel Lines" PPT download

Part One: Learning Objectives

1. Go through the discovery process of "isotropic angles are equal and two straight lines are parallel".

2. Master the method of determining parallel lines:

The parallel angles are equal and the two straight lines are parallel

Internal angles are equal and two straight lines are parallel

Interior angles on the same side are complementary and two straight lines are parallel

3. Flexibly use the three judgment methods of parallel lines to solve related problems

Parallel Lines PPT, Part 2: Review and Introduction to New Lessons

1. As shown in the figure: Find the concentric angles, internal offset angles, and congruent internal angles among the 8 angles intercepted by straight line a and b by straight line l.

2. What is two straight lines parallel? (What conditions must be met for two straight lines to be parallel?)

Definition and representation of parallel lines

In the same plane, two straight lines that do not intersect are called parallel lines.

Ask the students to read the book and think about it: How to show that two straight lines are parallel? How to read?

Representation of parallel lines:

AB∥CD

Line AB is parallel to line CD, or line AB is parallel to CD

a∥b

Line a is parallel to line b, or line a is parallel to line b

The essence of drawing parallel lines is to translate a straight line

The condition to ensure that the original figure is parallel to the image is: the same angles

Parallel Lines PPT, Part 3: How to Determine Parallel Lines

How to determine parallel lines 1: (Axiom)

If two straight lines are intercepted by a third straight line, if the angles are equal, then the two straight lines are parallel.

Abbreviation: the same angles are equal and the two straight lines are parallel

Using this axiom, the following reasoning can be made: as shown in the figure

∵ ∠1=∠2 (known)

∴ AB∥CD (the angles are equal and the two straight lines are parallel)

Method 2 for determining parallel lines:

If two straight lines are intercepted by a third straight line, if the internal offset angles are equal, then the two straight lines are parallel.

Abbreviation: internal angles are equal and two straight lines are parallel

Using this axiom, the following reasoning can be made: as shown in the figure

∵ ∠1=∠2 (known)

∴ AB∥CD (the internal offset angles are equal and the two straight lines are parallel)

Method 3 for determining parallel lines:

If two straight lines are intercepted by a third straight line, if the interior angles on the same side are complementary, then the two straight lines are parallel.

Abbreviation: interior angles on the same side are complementary and two straight lines are parallel

Using this axiom, the following reasoning can be made: as shown in the figure

∵ ∠1+∠2=180° (known)

∴ AB∥CD (interior angles on the same side are complementary and two straight lines are parallel)

Parallel Lines PPT, Part 4: Practice:

As shown in the figure, straight lines a, b, and c are intercepted by straight line d, and the measurement is ∠1=∠2=∠3.

(1) From ∠1=∠2, it can be concluded that which two straight lines are parallel?

What is the basis?

(2) From ∠1=∠3, it can be concluded that which two straight lines are parallel?

What is the basis?

(3) Are straight lines a, b, and c parallel to each other?

What is the basis?

Li Yili

What did you learn?

What else do you think you don’t understand?

What experiences and gains do you have that you can share with your classmates?

Keywords: Free download of Hebei Education Edition mathematics PPT courseware for seventh grade volume 2, parallel lines PPT download, .PPT format;

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"Properties of Parallel Lines" PPT download:

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"Properties of Parallel Lines" PPT:

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"Properties of Parallel Lines" PPT courseware download:

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Update Time: 2024-10-18

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

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