"Positional similarity of similar polygons and graphics" PPT courseware 2

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"Positional similarity of similar polygons and graphics" PPT courseware 2

1. If two ________ polygons ____________________ intersect at one point, we call the two figures similar figures. The intersection point is called ________, and the similarity ratio at this time is also called ________.

2. Similar figures are special similar figures, so two similar figures have all the properties of similar figures: corresponding sides ________, corresponding angles ________, the perimeter ratio is equal to ________, and the area ratio is equal to the square of ____________.

1. (3 points) Among the following propositions, which one is correct ()

A． Congruent figures must be similar figures

B． Similar figures must be similar figures

C. Similar figures must be congruent figures

D. Similar figures must be similar figures

2. (3 points) Among the following groups of figures, which one is not a similar figure ()

3. (3 points) The position-like center of a position-like figure can be in ()

A． Outside the original graphic B． within the original graphic

C. On the edge of the original figure D. All three of the above are possible

4. (3 points) As shown in the figure, with point O as the approximate center, the pentagon ABCDE is enlarged to obtain the pentagon A′B′C′D′E′. It is known that OA=10 cm, OA′=20 cm, Then the ratio of the perimeter of pentagon ABCDE to the perimeter of pentagon A′B′C′D′E′ is ________.

【Integrated use】

17． (12 points) As shown in the figure, the following method can be used to draw the inscribed equilateral triangle of △AOB. Answer the corresponding questions after reading.

Drawing method: ① Draw an equilateral triangle CDE in △AOB, so that point C is on OA and point D is on OB; ② Connect OE and extend it, intersect AB at point E′, and draw E′C′∥EC through point E′ , intersect OA at point C′, draw E′D′∥ED, intersect OB at point D′; ③Connect C′D′, then △C′D′E′ is the inscribed equilateral triangle of △AOB.

(1) Verify: △C′D′E′ is an equilateral triangle;

(2) Find the solution: the rectangle DEFG inscribed in the known △ABC, so that its side EF is on BC, vertices D and G are on AB and AC respectively, and DE:EF=1:2.

Keywords: Similar polygons and graphics teaching courseware, Hebei Education Edition ninth grade mathematics PPT courseware download, ninth grade mathematics slide courseware download, similar polygons and graphics PPT courseware download, .PPT format;

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"Positional Similarity of Similar Polygons and Figures" PPT courseware:

"Positional Similarity of Similar Polygons and Figures" PPT courseware 1. Two polygons with corresponding angles ________ and corresponding sides ________ are called ________. 2. The ratio of the perimeters of two similar polygons is equal to their __________; the ratio of the areas of similar polygons is equal to their _..

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Update Time: 2024-09-25

This template belongs to Mathematics courseware Hebei Education Edition Ninth Grade Mathematics Volume 1 industry PPT template

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