"Axisymmetry of Figures" PPT courseware

Description

"Axisymmetry of Figures" PPT courseware

1. Axisymmetric graphics

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 symmetrical figure.

The line along which the crease is located is called the axis of symmetry.

The axis of symmetry is a straight line! ! !

2. Examples in life

3. Question: Does an axially symmetric figure have to have only one axis of symmetry?

Conclusion: Some axisymmetric figures have only one axis of symmetry, but some axisymmetric figures have more than one axis of symmetry, and some axisymmetric figures even have countless axes of symmetry.

Use the method of folding in half to determine whether a figure is axially symmetrical

1. Are the following figures axially symmetrical? How do you judge?

For each of the above axisymmetric figures, can you find the axis of symmetry? What are the methods?

2. As shown in the figure, AD bisects ∠BAC, AB=AC. (1) Is the quadrilateral ABCD an axially symmetrical figure? If you think so, please name its axis of symmetry. Which point is symmetrical to point B?

In an axially symmetric figure, two points that can overlap after being folded along the symmetry axis are called symmetry points.

(2) Connect BC and intersect AD at point E. Fold the quadrilateral ABCD in half along AD. Do BE and CE coincide? What about ∠AEB and ∠AEC? What conclusion do you draw from this?

Properties of axially symmetric figures:

The axis of symmetry bisects the line segment connecting two points of symmetry perpendicularly.

If △ABC is folded along the straight line m, then △ A’B’C’ coincides with △ABC. At this time, we say that △ A’B’C’ and △ABC are axially symmetrical about the straight line m.

Generally speaking, changing from one figure to another and making the two figures overlap each other after being folded along a straight line is called axial symmetry of the figure.

This straight line is the axis of symmetry.

Two figures that are axially symmetrical are congruent figures.

The difference and connection between axially symmetrical figures and two figures forming axially symmetrical figures

Axisymmetric graphics Two graphics are axially symmetrical

Fold in half along a straight line so that the two folded parts completely overlap

Axisymmetric graphics

(1) Axisymmetric graphics refer to ( ) graphics with special shapes, only for ( ) graphics;

(2) There is only one axis of symmetry ( )

Two figures are axially symmetrical

(1) Axial symmetry refers to the positional relationship of the ( ) figure, which must involve the ( ) figure;

(2) There is only ( ) axis of symmetry.

connect

If an axially symmetric figure is divided into two parts along the axis of symmetry, then the two figures will be axially symmetrical about this straight line.

If two axially symmetrical figures are put together and viewed as a whole, then it is an axially symmetrical figure.

Keywords: teaching courseware on axial symmetry of graphics, Qingdao edition eighth grade mathematics volume PPT courseware download, eighth grade mathematics slide courseware download, axial symmetry of graphics PPT courseware download, .PPT format;

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

"Axisymmetric Symmetry of Figures" PPT courseware 3:

"Axisymmetric Symmetry of Figures" PPT Courseware 3 Learning Objectives 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 graphics are about a straight line..

"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..

File Info

Update Time: 2024-09-25

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

Preview