"Area of ​​Combined Figures" Area of ​​Polygons PPT Teaching Courseware

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"Area of ​​Combined Figures" Area of ​​Polygons PPT Teaching Courseware

Part One: Introduction to the topic

There are many combination graphics in life. Look at the picture above. What simple graphics are these combination graphics made of? How can we find their areas? Communicate in groups first, and then report back to the whole class.

Area of ​​combined graphics PPT, part 2 content: new teaching knowledge

way of expression:

method one:

There are two trapezoids separated in the middle. The area of ​​the team flag = the area of ​​the trapezoid + the area of ​​the trapezoid.

Method Two:

Connect the two corners of the flag with a straight line to make a large rectangle minus a triangle.

Method three:

Divide it into a large trapezoid and a triangle.

Summary of methods: segmentation method and supplementation method:

[Method Summary] In mathematics, we are accustomed to using the segmentation method or the addition method, and using auxiliary lines to transform a complex combined figure into a relatively simple figure, which brings simplicity to calculations. When drawing auxiliary lines, pay attention to drawing dotted lines, and use a pencil and ruler to draw.

Area of ​​combined graphics PPT, the third part: knowledge sorting

Knowledge point 1: Segmentation method.

You can divide a combined figure into several simple figures, find the areas of these simple figures respectively, and then sum them up.

Example: What is the area of ​​the safety exit sign? (unit cm)

[Analysis] This combined figure can be regarded as a triangle and a rectangle, and then find the areas of each and add them together.

Answer: 12×6+12×6÷2 =108 (cm²)

[Method summary] When using the segmentation method to calculate the area of ​​a combined figure, if it can be seen directly, there is no need to use auxiliary lines. If the figure is complicated, it is necessary to use auxiliary lines to analyze.

Knowledge point 2: Supplementary method.

The supplement method is to draw auxiliary lines to turn the combined figure into a large simple figure, and then use this large simple figure to subtract one or several simple small figures to find the area of ​​the combined figure.

Area of ​​combined graphics PPT, Part 4: Classroom exercises

1. Find the area of ​​the shaded part.

2. There is a vegetable field with a small pond in the middle, as shown on the right. On average, the vegetable field can produce 8 kilograms of vegetables per square meter. What is the area of ​​this field in square meters? How many kilograms of vegetables can this land produce?

Answer: 60×45=2700 (square meters)

(8+10)×7÷2=63 (square meters)

2700-63=2637 (square meters)

2637×8=21096 (kg)

3. Find the area of ​​the figure below.

Answer: 3×2÷2×5=15 (cm2)

Area of ​​combined graphics PPT, part 5 content: homework

1. Fill in the blanks.

(1) 0.96 hectare = ( ) square meter.

(2) The sum of the upper and lower bases of a trapezoid is 18 cm, the height is 6.8 cm, and the area is ( ) square centimeters.

(3) The base of the parallelogram is 2.5 decimeters, the height is 1.2 times the base, and its area is ( ) square centimeters.

2. Find the area of ​​the figure below. (Unit: cm)

32×20+32×10÷2=800 (cm²) 12×10-(8+3)×2÷2=109 (cm²)

3. Two identical trapezoids, the upper base is 23 cm long, the lower base is 27 cm long, and the height is 20 cm. If these two trapezoids are put together to form a parallelogram, what is the area of ​​the parallelogram?

Answer: (23+27)×20=1000 (square centimeters)

Area of ​​combined graphics PPT, part 6: knowledge expansion

There is a rectangular open space on campus, where it is planned to plant lawns and lay tiles (as shown on the right). Please find the area of ​​the lawn and the area of ​​the tiled floor respectively.

Area of ​​tiles: (3+20)×12÷2=138 (m²)

Lawn area: 20×12-138=102 (m²)

Keywords: free download of PPT courseware for mathematics in the first volume of the fifth grade of the People's Education Press, PPT download of the area of ​​combined shapes, PPT download of the area of ​​polygons, .PPT format;

For more information about the "Area of ​​Combined Figures Area of ​​Polygons" PPT courseware, please click on the Area of ​​Combined Figures PPT Area of ​​Polygons PPT tab.

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Update Time: 2024-11-25

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

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