"Understanding of Trapezoid" Parallelogram and Trapezoid PPT Courseware

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"Understanding of Trapezoid" Parallelogram and Trapezoid PPT Courseware

Part One Content: Review Introduction

Fold the parallelogram paper along the dotted line and observe this figure. Do you know what this quadrilateral is called?

In this lesson, we will learn about trapezoids.

Have you ever seen a trapezoid in your life?

What shape did you find in the picture? Can you point it out?

PPT on understanding trapezoids, part 2: exploring new knowledge

1. Study the characteristics of trapezoids.

(1) Make a trapezoid: Can you make a trapezoid?

(2) Talk about characteristics: When you were making the trapezoid just now, did you find any essential characteristics of the trapezoid?

Answer: One set of opposite sides is parallel but not equal in length, and the other set of opposite sides is not parallel.

There are four sides and four corners, one set of opposite sides is parallel and the other set of opposite sides is not parallel.

(3) Compare similarities and differences: What is the difference between a trapezoid and a parallelogram?

Answer: A quadrilateral with only one set of parallel sides is called a trapezoid.

A quadrilateral with two opposite sides that are parallel is called a parallelogram.

(2) Know the names of each part of the trapezoid.

[Method Summary] A set of opposite sides that are parallel to each other is called the base of a trapezoid. According to the position of the graphics, the one above is generally called the upper bottom, and the one below is called the lower bottom. It is customary to draw the upper base shorter and the lower base longer. A set of opposite sides that are not parallel is called the waist. Draw a vertical line from a vertex of the upper base to the opposite side. The line segment between this point and the vertical foot is called the height of the trapezoid.

think about it

①How many lines like this can be drawn? ② Can you draw height on the waist of the trapezoid?

Answer: The height of a trapezoid can only be determined by drawing a vertical line from a point on one of the two parallel sides to its opposite side. There are countless vertical lines.

(3) Understanding special trapezoids

[Method summary] A trapezoid with two equal sides is called an isosceles trapezoid. A trapezoid with two right angles is called a right-angled trapezoid. They are two special types of trapezoids, and the isosceles trapezoid is an axially symmetrical figure.

(4) Understand the relationship between quadrilaterals

PPT on understanding trapezoids, part 3: consolidation exercises

1. True or False Question

(1) There is a set of parallel quadrilaterals called a trapezoid. ( )

(2) All trapezoids are not axially symmetrical figures. ( )

(3) There are two right angles in a right trapezoid. ( )

Summary of the whole lesson

What did you learn in this lesson? What learning methods did you use? What else are you confused about?

Get to know the trapezoid

Trapezoid: a quadrilateral with only one set of parallel sides

Special trapezoid: Isosceles trapezoid (axisymmetric figure)

Right trapezoid (has two right angles)

Understanding the trapezoid PPT, the fourth part: knowledge sorting

1. A trapezoid refers to a quadrilateral in which one set of opposite sides is parallel and the other set of opposite sides is not parallel. There are two conditions for judging a trapezoid: ① it must be a quadrilateral; ② there is and only one set of opposite sides that are parallel.

2. The two parallel sides are called the base of the trapezoid, the shorter side is called the upper base, and the longer side is called the lower base; the two non-parallel sides are called the waist; the vertical segment between the two bases is called the height of the trapezoid. .

3. A trapezoid with one waist perpendicular to the base is called a right-angled trapezoid, and a trapezoid with two equal sides is called an isosceles trapezoid.

Isosceles trapezoid is a special kind of trapezoid, and its determination method is similar to that of isosceles triangle.

4. The connection and difference between trapezoid and parallelogram:

PPT on understanding trapezoids, part 5: analysis of examples

Example 1: Judgment: Two identical trapezoids can be combined to form a parallelogram. ( )

[Analysis] The test point of this question is the assembly of graphics. Because the opposite sides of a parallelogram are parallel and equal, two identical trapezoids can have the waist as a common side, and their upper and lower bases are respectively opposite to the lower and upper bases of the other trapezoid. Since the upper and lower bases of the trapezoid are parallel , the pair of the formed figure (upper base + lower base) is equal to (lower base + upper base), and is parallel, so the formed figure is a parallelogram. So the answer is: correct.

judge.

(1) Only two identical trapezoids can be combined into a parallelogram. ( )

(2) Any two trapezoids can be combined to form a parallelogram. ( )

(3) Two identical right-angled trapezoids can be combined into a rectangle. ( )

Example 2: Judgment

There are countless heights of a trapezoid, and they are all equal.

[Analysis] This question focuses on the characteristics of the trapezoid. According to the meaning of the height of a trapezoid, pick any point on the upper base of the trapezoid and draw a vertical line segment downward from this point to the base to determine the height of the trapezoid. There can be countless such line segments, so a trapezoid can draw countless heights, and because the upper and lower bases of the trapezoid are parallel to each other, these heights are all equal. Based on this, the answer is that there are countless heights of a trapezoid, and they are all equal. The statement is correct.

PPT on the understanding of trapezoids, part 6: exercises to consolidate

basic exercises

(1) Draw a line segment in an isosceles trapezoid, which can be divided into two identical ones ( ).

A.Trapezoid B.Parallelogram C.Triangle

(2) Which of the following statements is correct ( ).

A． A parallelogram is a special kind of trapezoid

B. The two base angles of an isosceles trapezoid are equal

C． An isosceles trapezoid cannot be a right-angled trapezoid

D． A trapezoid with two adjacent angles that are equal is an isosceles trapezoid

Expand and improve

1. In the isosceles trapezoid, the following conclusions are made:

①The two waists are equal; ②The two bases are parallel; ③The diagonals are equal; ④The two base angles are equal.

Among them, there are ( ) correct ones

A． 1B. 2C. 3D． 4

2. Draw a right-angled trapezoid with an upper base of 4 cm, a lower base of 5 cm, and a height of 3 cm.

divergent thinking

1. Give one point as required.

(1) Draw a line segment in the picture below and divide it into two triangles

(2) Draw a line segment in the picture below and divide it into a parallelogram.

Keywords: Free download of PPT courseware for mathematics in the first volume of the fourth grade of the People's Education Press, PPT download on the understanding of trapezoids, PPT download of parallelograms and trapezoids, .PPT format;

For more information about the "Understanding of Parallelograms and Trapezoides" PPT courseware, please click on the "Understanding of Parallelograms and Trapezoids" PPT tag.

"Understanding of Trapezoid" Parallelogram and Trapezoid PPT:

"Understanding of Trapezoid" Parallelogram and Trapezoid PPT Part One Content: Exciting Introduction What are the characteristics of parallelogram? The two opposite sides of a parallelogram are parallel and equal to each other. The base and height of a parallelogram correspond to each other. There are countless heights on a base...

"Understanding of Parallelogram and Trapezoid" Parallelogram and Trapezoid PPT Courseware 2:

"Understanding of Parallelogram and Trapezoid" Parallelogram and Trapezoid PPT Courseware 2 A quadrilateral with two sets of opposite sides that are parallel is called a parallelogram. Find the similarities and differences between parallelograms and trapezoids. Similar points: both have four sides and four angles. Different points: parallelograms..

"Understanding Parallelograms and Trapezoids" Parallelograms and Trapezoid PPT Courseware:

"Understanding Parallelograms and Trapezoids" Parallelograms and Trapezoid PPT Courseware A quadrilateral with two sets of opposite sides that are parallel is called a parallelogram. A quadrilateral with only one set of parallel sides is called a trapezoid. Think about it: What do rectangles, squares and parallelograms have in common?

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Update Time: 2024-09-30

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