"Side Development Views of Cylinders and Cones" PPT Courseware 3

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"Side Development Views of Cylinders and Cones" PPT Courseware 3

Review review:

1. What is the arc length formula?

2.What is the formula for the area of ​​a sector?

3. What is the lateral area of ​​a prism?

Structural features of cylinders

Cylinder: The geometry formed by the straight line where one side of the rectangle is located is the axis of rotation, and the curved surface formed by the rotation of the other three sides is called a cylinder.

Cylinders and prisms are collectively called cylinders.

A cylinder is represented by a letter indicating its axis. For example, cylinder OO’

Structural features of a cone

Cone: The geometry surrounded by the curved surface formed by the rotation of the other two sides is called a cone.

A cone is represented by a letter indicating its axis.

Cones and pyramids are collectively called cones

There is a circular oil tank with a bottom circle circumference of 24m and a height of 6m. A mouse crawls from A, 1m away from the bottom, to diagonal B to eat food. What is the shortest route it can crawl?

Analysis: Since the mouse crawls along the surface of the cylinder, the cylinder needs to be expanded into a plane figure. According to the shortest line segment between the two points, it can be found that A and B are respectively at the width of 1m and the length of 24m in the expanded view of the side of the cylinder. point, that is, the length AB is the shortest route. (As shown in the figure)

AC = 6 – 1 = 5,

BC = 24 ×1/2= 12,

From the Pythagorean theorem

AB2= AC²+ BC²=169,

∴AB=13(m) .

Give it a try, I can do it

1. If the sum of the areas of the two bases of a cylinder is equal to the side area, then the ratio of the generatrix to the diameter of the base is equal to ________.

2. Use two pieces of congruent rectangular paper to roll into two cylinders with different shapes (ie, the sides of the cylinder). Suppose the side area and base radius of the taller cylinder are S1 and r1 respectively, and the side area and base radius of the shorter cylinder are S2 and R2 respectively, then ( )

(A) S1 =S2,r1 = R2 (B) S1 = S2,r1>R2

(C) S1 = S2,r1＜R2 (D) S1≠S2,r1 = R2

3. A rectangular cardboard with two sides of 2cm and 4cm respectively. The surface area of ​​the geometric body formed by rotating around the straight line of one side is ( )

(A)24πcm² (B) 24πcm2 or 48πcm²

(C)20πcm² (D) 20πcm2 or 48πcm²

Keywords: teaching courseware of side expansion diagrams of cylinders and cones, Qingdao edition ninth grade mathematics volume 2 PPT courseware download, ninth grade mathematics slide courseware download, side expansion diagrams of cylinders and cones PPT courseware download, .PPT format;

For more information about the PPT courseware "Side Exploded Views of Cylinders and Cones", please click the Developed Side Views of Cylinders and Cones PPT tab.

"Side Development Views of Cylinders and Cones" PPT Courseware 2:

"Side Development of Cylinders and Cones" PPT Courseware 2 Review Review A three-dimensional body whose surface is composed of a curved surface or a curved surface and a plane is called a curved body. Common curved bodies include cylinders, cones, spheres, and rings. Observation and Thinking 1 Compare the structural characteristics of pyramids, observe and think about circles...

"Side Development Views of Cylinders and Cones" PPT courseware:

"Side Development of Cylinders and Cones" PPT courseware Learning objectives 1. Understand the concepts and properties of cylinders and cones, and understand the base and side surfaces of cylinders and cones. 2. Understand the side expansion diagrams of cylinders and cones, and be able to imagine actual objects based on the expansion diagrams. 3. Can calculate...

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Update Time: 2024-09-05

This template belongs to Mathematics courseware Qingdao Edition Ninth Grade Mathematics Volume 2 industry PPT template

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