"Axisymmetry" PPT courseware 3

Description

"Axisymmetry" PPT courseware 3

Accurate description of the concept of axial symmetry

Fold a figure along a certain straight line. If it can coincide with another figure, then the two figures are said to be symmetrical about this straight line.

Corresponding points in the two figures are called symmetry points about this line.

This straight line is called the axis of symmetry. Symmetry between two figures about a straight line is also called axial symmetry.

Concept understanding and induction

Axial symmetry involves two figures that completely coincide with each other. Therefore, axial symmetry refers to the shape and positional relationship between the two figures.

The concept has restrictions on the overlap of two figures. Their positional relationship must be such that they can overlap after being folded in half along a certain straight line.

Observe graphic induction properties

Judging from the size and shape of the two figures:

Theorem 1. Two figures that are symmetrical about a certain straight line are congruent shapes.

From the position of the two figures:

Theorem 2. If two figures are symmetrical about a straight line, then the axis of symmetry is the perpendicular bisector of the line connecting the corresponding points.

Looking at the axis of symmetry:

Theorem 3. Two figures are symmetrical about a certain straight line. If their corresponding lines or extended lines intersect, then the intersection point is on the axis of symmetry.

Thoughts after class:

1. Fold in half along the height of the base of the isosceles triangle. Do the shapes on both sides of the height completely overlap?

2. Fold in half along the height on the hypotenuse of the right-angled triangle. Do the shapes on both sides of the height completely overlap?

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"Axisymmetric" PPT:

"Axisymmetric" PPT Part 1 Content: New Lesson Introduction What characteristics did you find of these buildings? There are many symmetrical things and phenomena in life. Boats, people, plants and reflections in the water are all symmetrical. Take a small mirror and place it on an axially symmetrical figure or object...

"Axisymmetry" PPT courseware 6:

"Axisymmetric" PPT Courseware 6 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 the straight line is called the axis of symmetry. Practice it. The following figures are all axially symmetrical figures. Please find out...

"Axisymmetric" PPT courseware 5:

"Axisymmetric" PPT courseware 5 Review of old knowledge What is an axially symmetric figure? What is the axis of symmetry? If a figure is folded along a straight line and the parts on both sides of the straight line can completely overlap, the figure is called an axially symmetric figure. This straight line is called the axis of symmetry.

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Update Time: 2024-09-23

This template belongs to Mathematics courseware People's Education Press Eighth Grade Mathematics Volume 1 industry PPT template

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