"Area of ​​a Circle" Circumference and Area of ​​a Circle PPT Courseware

Description

"Area of ​​a Circle" Circumference and Area of ​​a Circle PPT Courseware

teaching objectives

1. Experience the process of estimating the area of ​​a dart board, hands-on operations, discussions, etc. to explore the formula for calculating the area of ​​a circle.

2. Understand and master the formula for the area of ​​a circle, and be able to use the formula to calculate correctly.

3. Experience the feasibility of deriving the circle area formula and the certainty of the conclusion, and experience mathematical ideas such as transformation and infinite division.

Estimate the area of ​​the dartboard.

Look at the dart board and tell me what you found?

Make an estimate: What is the approximate surface area of ​​this dart board in square centimeters?

Perimeter of flying target board:

2×3.14×10=62.8 (cm)

Area of ​​small triangle:

62.8×1/20×10÷2=15.7 (square centimeters)

Flying mark board area:

15.7×20=314 (square centimeters)

In conclusion

1. The size of the surface of a circular object or the plane occupied by a circular object or figure is called the area of ​​a circle.

2. When estimating the area of ​​the dart board, we found that after dividing the circle into several equal parts, the resulting figure is close to a rectangle. The length of the rectangle is close to half the circumference and the width is close to the radius of the circle. The area of ​​the circle can be estimated based on the area of ​​the rectangle.

give it a try

Calculate the area of ​​the dartboard using the formula for the area of ​​a circle.

practice

1. Find the area of ​​each circle below.

2. A circular rotating exhibition stand with a table radius of 3 meters. What is the area of ​​the table in square meters?

3.14×3²=28.26 (square meters)

Answer: The area of ​​the countertop is 28.26 square meters.

3. Uncle Wang wants to build a circular fish pond with a radius of 22 meters. Do the math: How many square meters does this fish pond occupy?

3.14×22²＝1519.76 (square meters)

Answer: This fish pond covers an area of ​​1519.76 square meters.

4. Use a compass to draw a circle yourself and then calculate its area.

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For more information about the PPT courseware "Perimeter and Area of ​​a Circle and Area of ​​a Circle", please click the Perimeter and Area of ​​a Circle ppt Area of ​​a Circle ppt tag.

"Area of ​​a Circle" Circle PPT Courseware 6:

"Area of ​​a Circle" Circle PPT Courseware 6 The calculation of the area of ​​a circle has a wide range of applications in life. Please look at the following example: To make a cylindrical bucket, Master Li needs a round piece of tinplate with a diameter of 40 cm to make the bottom of the bucket. This kind of iron sheet costs 50 yuan per square meter..

"Area of ​​a Circle" Circle PPT Courseware 5:

"Area of ​​a Circle" Circle PPT Courseware 5 The spray radius is 3m. If the sprinkler head rotates once, how much area of ​​farmland can be irrigated? 3.143=3.149=28.26 (m) Answer: It can irrigate 28.26 square meters of farmland. The circumference of the circular sheepfold was measured to be 125.6m. The face of this sheepfold...

"Area of ​​a Circle" Circle PPT Courseware 4:

"Area of ​​a Circle" Circle PPT Courseware 4 How to get the area of ​​a circle? Think about it and talk to your peers. The area of ​​a circle is a little more than three times the area of ​​a square (radius squared). The area of ​​the circle ---- the area of ​​the parallelogram The area of ​​the parallelogram = base height ..

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Update Time: 2024-10-18

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

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