"Properties of Parallel Lines" PPT courseware download

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"Properties of Parallel Lines" PPT courseware download

Part One: Try it out

Experiment: Select any two parallel lines a and b on the prepared lined notebook

(1) Draw an arbitrary straight line c that intersects the parallel lines a and b.

(2) Choose any pair of co-positioned angles and measure them with a protractor to see what is the relationship between this pair of co-positioned angles?

Conclusion: Two parallel lines are intercepted by a third straight line, and their angles are equal.

1. Properties of parallel lines 1:

Two parallel lines intersected by a third straight line have equal angles.

Simply put: two straight lines are parallel and have equal angles.

Think about answering the following questions:

(1) Properties of parallel lines (1) What is known? What was the conclusion?

(2) What is the difference between it and the judgment that two straight lines are parallel that we learned earlier, "the two straight lines are parallel if the angles of the same angle are equal"?

∵ AB//CD (known)

∴∠1=∠2 (two straight lines are parallel and have equal angles)

PPT on the properties of parallel lines, part 2: discussion of issues

Please think about it: if two parallel lines are intercepted by a third straight line, what is the relationship between interior angles on opposite sides and interior angles on the same side?

As shown in the figure, given the straight line a//b, think about the relationship between ∠1 and ∠2, ∠2 and ∠3? Why?

(1) ∵ a//b (known)

∴∠2=∠4 (two straight lines are parallel and have equal angles)

And ∵∠1=∠4 (the two vertex angles are equal)

∴∠1=∠2

Conclusion: Two parallel lines are intercepted by a third straight line, and their internal offset angles are equal.

Parallel Line Property 2: Two straight lines are parallel and their internal offset angles are equal.

(2) ∵ a//b (known)

∴∠2=∠4 (two straight lines are parallel and have equal angles)

And ∵∠4+∠3=1800 (definition of adjacent supplementary angles)

∴∠2+∠3 =1800

Think about other ways?

Conclusion: Two parallel lines are intercepted by a third straight line, and the interior angles on the same side are complementary.

3. Parallel Line Property 3: Two straight lines are parallel and the interior angles on the same side are complementary.

PPT on the properties of parallel lines, part 3: Class summary

1. Three properties of parallel lines:

Two straight lines are parallel and have equal angles.

Two straight lines are parallel and their interior angles are equal.

Two straight lines are parallel and their interior angles on the same side are complementary.

2. The difference between the properties of parallel lines and the determination of parallel lines.

Judgment: Angular relationship → Parallel relationship

Properties: parallel relationship → angular relationship

3. To prove parallelism, use judgment. To know parallelism, use properties

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"Properties of Parallel Lines" PPT download:

"Properties of Parallel Lines" PPT Download Part 1 Content: Review Review What are the methods for determining parallel lines? How to identify parallel lines: (1) the angles of the same angles are equal, two straight lines are parallel (2) the internal angles are equal, the two straight lines are parallel (3) the internal angles on the same side are complementary, Two straight lines are parallel...

"Properties of Parallel Lines" PPT:

"Properties of Parallel Lines" PPT Part One Content: Knowledge Review 1. If B=1, according to _______________, we can get AD//BC 2. If 1=D, according to _______________, we can get AB//CD 3. If B+BCD=180, according to___..

"Property Theorem and Determination Theorem of Parallel Lines" PPT courseware 3:

"The Property Theorem and Determination Theorem of Parallel Lines" PPT Courseware 3 Knowledge Review: (1) What is a proposition? How many categories can propositions be divided into? (2) What parts does a proposition consist of? (3) What is the general narrative form of a proposition? Let's talk about it. If two angles are right angles...

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Update Time: 2024-10-20

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

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