"Axisymmetry of Figures" PPT courseware 3

Description

"Axisymmetry of Figures" PPT courseware 3

learning target

1. Through life examples, experience the process of abstracting the concept of axial symmetry and the axial symmetry of two figures about a straight line, and be able to identify the symmetry axis and symmetry point.

2. Can determine whether two figures are axially symmetrical about a certain straight line.

3. Can solve some simple problems by using whether two figures are axially symmetrical about a certain straight line.

[Exploration activity 1]

Do it

First put a drop of ink on a piece of paper, then fold it in half and flatten it, then open it again and observe the relationship between the two drops of ink.

[Exploration Activity 2]

1. Take a rectangular piece of paper and follow the steps below.

Fold the rectangular piece of paper in half, with the crease at ,

(1) Draw △ABC on paper;

(2) Use the tip of a needle to poke several small holes along each vertex of △ABC

(3) Unfold the paper and connect AA’, BB’, CC’

2. Explore:

Question 1: In the picture, what is the relationship between line segments AB and A’B’? What about BC and B’C’? What about AC and A’C’? Tell us your reasons.

Question 2: In the picture, what is the relationship between ∠A and ∠A’? What about ∠B and ∠ B’? What about ∠C and ∠ C’? What is the relationship between △ABC and △A’B’C’? Why?

1. Axial symmetry:

After folding a figure along a certain straight line, another figure that is congruent to it is obtained. This change in the figure is called axial symmetry.

This straight line is called the axis of symmetry.

Axial symmetry is a change in graphics.

2. Two figures are axially symmetrical about a certain straight line

A figure takes a certain straight line as the axis of symmetry. After being axially symmetrical, it can overlap with another figure. It is said that the two figures are axially symmetrical about this straight line, and the overlapping points are called corresponding points. In particular, if two points are axially symmetric about a straight line, one of the points is called the symmetry point of the other point about the straight line.

think:

1. Are two axially symmetric figures necessarily congruent? Why?

2. Do two congruent shapes have to be axially symmetrical? for example.

Two figures that are axially symmetrical are congruent shapes, but congruent shapes are not necessarily axially symmetrical figures.

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For more information about the "Axisymmetric Symmetry of Graphics" PPT courseware, please click the "Axisymmetric Symmetry of Graphics" ppt tag.

"Axisymmetric Figures" PPT Courseware 2:

"Axisymmetric Figures" PPT Courseware 2 If a figure is folded along a straight line and the parts on both sides of the straight line can overlap each other, then the figure is called an axially symmetric figure, and this straight line is its axis of symmetry. Use the method of folding in half to determine whether a figure is axially aligned..

"Axisymmetric Symmetry of Figures" PPT courseware:

"Axisymmetric Figures" PPT Courseware 1. Axisymmetric Figures 1. Concept: If a figure is folded in half along a straight line and the figures on both sides can completely overlap, the figure is an axially symmetric figure. The line along which the crease is located is called the axis of symmetry. The axis of symmetry is...

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Update Time: 2024-07-05

This template belongs to Mathematics courseware Qingdao Edition Eighth Grade Mathematics Volume 1 industry PPT template

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