"Perimeter of a Circle" Circle PPT Download

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"Perimeter of a Circle" Circle PPT Download

Part One: Introduction to the topic

The round table and cutting board are a little cracked and need a ring of iron around their edges.

How many lengths of iron sheets are needed?

What mathematical questions can be asked based on the information in the figure?

Circumference of a circle PPT, part 2 content: new teaching knowledge

Perimeter of square/rectangle

Refers to the total length of their four sides or a week.

circumference of circle

The length of the curve surrounding a circle is called the circumference of the circle or the length of a circle. Indicated by the letter "C".

Please think about what the circumference of a circle is related to?

Zu Chongzhi was a great mathematician in ancient my country. He initially calculated that pi was 22/7≈3.142857... He was not satisfied and thought that the result was not very accurate. After repeated experiments and calculations, he finally calculated that pi was 355/113≈3.141592. ..., it is an odd number 1, 3, 5. Each number is repeated 2 times 113355, separated in the middle, with the denominator in front and the numerator in the back. This score is the most beautiful and valuable score in the world.

Circumference of a circle PPT, part 3: comprehensive exercises

1. True or False Questions

(1) The circumference of a circle is π times its diameter. ( )

(2) Pi is equal to 3.14. ( )

(3) The circumference of the semicircle is half of the circumference of the circle. ( )

2. Fill in the blanks

(1) If the diameter of a circle is expanded by 2 times, its circumference will be expanded by ( ) times.

(2) Cut the largest circle on a square paper with a side length of 8 cm. Its diameter is ( ) cm and its circumference is ( ) cm.

Circumference of a circle PPT, part 4 content: application practice

Example 1: It is known that the radius of a bicycle wheel is approximately 33 cm. Approximately how far can this bicycle wheel rotate once? (Keep the whole meter in the result.) Xiao Ming’s home is 1 kilometer away from the school. How many turns does the wheel make?

[Analysis] To find out how far a bicycle wheel goes when it makes one revolution, that is to find out what is the circumference of the wheel? To find the approximate number of revolutions of the wheel, that is, how many circumferences of the wheels are required in 1 kilometer?

Example 2: Given that the circumference of the table is 4.71 meters, can you find its diameter?

[Analysis] You can use division operations or equation calculations. Both methods require the formula for the circumference of a circle, that is, C=dπ. If division is not possible, two decimal places should be retained.

Example 3: As shown in the figure, there is a semicircle with a radius of 5 cm. Find its circumference.

[Analysis] The key to answering this question is that a semicircle is surrounded by a half arc and a diameter. The circumference of the semicircle is equal to the circumference of the half circle plus the diameter of the circle.

Knowledge points

1. The length of the curve surrounding a circle is called the circumference of the circle or the length of a circle, represented by the letter c.

2. π≈3.14 C=dπ=2πr

Circumference of a circle PPT, part 5: knowledge sorting

Knowledge point: How to calculate the circumference of a circle

Example 1: In a circular pavilion, Xiaoli walked 12 steps along the diameter from one end to the other end. Each step is about 55cm long. What is the approximate circumference of this circle in meters?

55×12×3.14=2072.4 (cm) ≈ 21 (m)

[Analysis] Xiaoli walked 12 steps along the diameter from one end to the other. The length of each step is about 55 cm. It can be seen that the diameter of the circular pavilion is 55×12=660 (cm). According to ?=??, then Can find the circumference.

Example 2: To install decorative wooden strips on a door of Li Ming’s house, how many meters of wooden strips are needed? (as the picture shows)

C=dπ= 50×3.14 = 157 cm

[Analysis] This graphical calculation requires the door to be equipped with decorative wooden strips shaped like the picture below. First, it requires the circumference of the semicircle above, plus the circumference of the three sides of the square.

Circumference of a circle PPT, Part 6 content: Classroom exercises

1. Fill in the blanks

(1) The length ( ) that forms a circle is called the circumference of the circle.

(2) To measure the circumference of a circle, you can use the ( ) method and the ( ) method.

(3) The ratio of the circumference of a circle to its diameter is called ( ), represented by the letter ( ).

(4) The circumference of a circle is ( ) times the diameter of the circle, and the circumference is ( ) times the radius of the circle.

(5) Surround a metal strip around the edge of a round tabletop. The length of the metal strip is equal to ( ) of the round tabletop.

2. Select

(1) Who was the first person to measure pi to seven decimal places? ( )

A. Chongzhi B. Hua Luogeng C. Zhou Enlai D. Edison

(2) Xiao Ming walked around the edge of a circular flower bed with a radius of 5 meters. Approximately how many meters did he walk? ( )

A. 5 meters B. 10 meters C. 31.4 D. 62.8 meters

(3) Aunt Yang built a fence around a semicircular vegetable plot with a radius of 10 meters. How many meters long is the fence? ( )

A. 31.4 meters B. 62.8 meters C. 41.4 meters D. 51.4 meters

Keywords: Free download of PPT courseware for sixth grade mathematics from the People's Education Press, download of PPT on the circumference of a circle, download of circle PPT, .PPT format;

For more information about the "Perimeter of a Circle" PPT courseware, please click on the Circle PPT Circumference of a Circle PPT tab.

"Perimeter of a Circle" circle PPT courseware download:

"Perimeter of a Circle" Circle PPT courseware download Part One: Preparation before class Learning focus: Explore and discover the relationship between the circumference and diameter of a circle. Learning difficulties: Use the circumference of a circle to solve some simple practical problems. Learning methods: Use rolling, winding and other methods..

"Perimeter of a Circle" Circle PPT teaching courseware:

"Perimeter of a Circle" Circle PPT Teaching Courseware Part One: Situation Introduction People have long discovered that the bigger the wheel, the farther it rolls in one circle. What did you find? The length of one revolution of the wheel is its circumference. ... ... ... Circumference of a circle PPT, Part 2...

"Perimeter of a Circle" Circle PPT Courseware (Lesson 2):

"Circumference of a Circle" Circle PPT Courseware (Lesson 2) Part One: Classroom Introduction 1. Through independent exploration, everyone will understand the meaning of pi and the formula for calculating the circumference of a circle. 2. Be able to apply formulas to solve practical problems in life. 3. Combined with Zu Chongzhi’s story,...

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Update Time: 2024-11-18

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

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