Similar PPT courseware for the graphics "Proportional Line Segment" 4

Description

Similar PPT courseware for the graphics "Proportional Line Segment" 4

Review before class

If the ratio of two numbers is equal to the ratio of two other numbers, the four numbers are said to be proportional.

We proportion the four numbers a, b, c, and d, a/b=c/d

a and d are called proportional external terms

There are two ways to determine whether four line segments are proportional:

(1) Arrange the four line segments according to size and determine whether the ratio of the first two line segments is equal to the ratio of the last two line segments.

(2) Check whether the product of two line segments is equal to the product of the other two line segments.

It is known that point C is the golden section point of line segment AB, and AC>CB, then the following equation holds ( )

(A) AB=AC·CB (B) CB=AC·AB

(C) AC=CB·AB (D) AC2=AB·BC

The profound significance of the golden section

Historically, people regarded the golden section as the "most beautiful" geometric ratio, which was widely used in architecture and sculpture, such as the Parthenon in ancient Greece, the Egyptian Pyramids, the Oriental Pearl Tower in Shanghai, etc. Some rectangular picture frames are as wide as The length ratio is also designed to be 0.618. There are many examples in nature. The ratio of the body length of a beautiful butterfly to the length of its wings when spread out is about 0.618. Many beautiful shapes are related to the ratio of 0.618.

Expand new knowledge

1. Construct an isosceles △ABC with a vertex angle of 36°; measure the length of the base BC and waist AB, and calculate: BC/AB≈0.618;

2. Draw the bisector of ∠B, intersect AC at point D, measure the length of CD, and then calculate: CD/BC≈0.618. (accurate to 0.001)

An isosceles triangle with a vertex angle of 36° is called a golden triangle

Point D is the golden section of line segment AC.

Then draw the bisector of ∠C and intersect BD at E, △CDE is also a golden triangle...

Talk about feelings and take stock of gains

1. The concept of the middle term of proportion.

2. The difference between the median of the proportion of a line segment and the median of the proportion of a number;

3.What is the golden section.

4. How to determine the golden section point or golden ratio.

5. Use mathematical beauty to decorate and beautify life.

Keywords: similar teaching courseware of graphics, teaching courseware of proportional line segments, Beijing Normal University version of ninth grade mathematics volume 1 PPT courseware, download of ninth grade mathematics slide courseware, download of similar PPT courseware of graphics, download of proportional line segment PPT courseware, .ppt Format

For more information about the PPT courseware "Similar Proportional Line Segments of Graphs", please click the "Similar Proportional Line Segments of Graphs" ppt tag.

Similar PPT courseware 3 of the "Proportional Line Segment" graphic:

"Proportional Line Segments" Similarity of Figures PPT Courseware 3 Knowledge Review If the ratio of two numbers is equal to the ratio of the other two numbers, it is said that the four numbers are proportional. We put the four numbers a, b, c, d into In proportion, a and d are called the external terms of the proportion, and b and c are called the internal terms of the proportion..

Similar PPT courseware 2 for the graphic "Proportional Line Segment":

"Proportional Line Segment" Similarity PPT courseware of graphics 2 Explore new knowledge Calculation: (1) The ratio of -3 to 2; (2) The ratio of 6 to -4. Are their ratios equal? Like this, if the ratio of two numbers is equal to the ratio of two other numbers, then we say that the four numbers are proportional. ..

Similar PPT courseware for the graphic "Proportional Line Segment":

"Proportional Line Segments" PPT courseware for similar figures. Congruent shapes refer to two figures that can completely overlap, that is, their shapes and sizes are exactly the same. What characteristics do these figures have in common? They have the same shape and different sizes, but the lengths of the segments are proportional...

File Info

Update Time: 2024-10-05

This template belongs to Mathematics courseware Beijing Normal University Ninth Grade First Volume Mathematics industry PPT template

Preview