"Circle and the Positional Relationship of Circles" Circle PPT Courseware

Description

"Circle and the Positional Relationship of Circles" Circle PPT Courseware

teaching objectives

knowledge and abilities

Master the circle and the five positional relationships of the circle.

Process and Method

Observe the changing process of the positional relationship between the two circles, feel the quantitative relationship between the radius of the two circles and the distance between the centers of the circles in various relationships, and thus obtain the connection between the "positional relationship" and "quantitative relationship" of the graphics.

Emotional attitudes and values

Through observation, comparison and hands-on operations, students can feel that mathematical activities are full of imagination and exploration, and feel the necessity and rigor of proof and the certainty of mathematical conclusions.

Theorem Proof

Proof: Suppose the tangent point T is not on O1O2.

∵A circle is an axially symmetrical figure,

The symmetry point T′ of ∴T about O1O2 is also two

The common point of the circle, which contradicts the known conditions ⊙O1 and ⊙O2 are tangent,

∴Assumption is not true.

Then T is on O1O2.

∴It can be seen that Figure (1) is an axially symmetrical figure, and the axis of symmetry is the line connecting the centers of the two circles.

The positional relationship between the tangent point and the axis of symmetry is that the tangent point is on the axis of symmetry.

The same conclusion should be drawn in Figure (2).

Practice in class

1. The radii of ⊙O1 and ⊙O2 are 3 cm and 4 cm respectively, assuming

(1) O1O2=8cm; outside

(2) O1O2=7 cm; circumcision

(3) O1O2=5 cm; intersect

(4) O1O2=1 cm; incision

(5) O1O2=0.5 cm; included

(6) O1 and O2 coincide. concentric circles

What is the positional relationship between ⊙O1 and ⊙O2?

2. The radius of ⊙O is 5cm, point P is a point outside ⊙O, OP=8cm, find

(1) Taking P as the center of the circle and making circumsections of ⊙P and ⊙O, what is the radius of the small circle ⊙P?

(2) Taking P as the center of the circle and inscribing ⊙P and ⊙O, what is the radius of the great circle ⊙P?

3． The radius of fixed circle O is 4 cm, and the radius of moving circle P is 1 cm.

(1) Assume that ⊙P and ⊙O are circumstantial, then what is the distance between point P and point O? On what line can point P move?

(2) Suppose ⊙P and ⊙O are inscribed in phase, what is the situation?

Keywords: circle and the positional relationship courseware of a circle, circle courseware, New People's Education Press ninth grade mathematics volume PPT courseware, ninth grade mathematics slide courseware download, circle and the positional relationship of a circle PPT courseware download, circle PPT courseware download, .ppt Format

For more information about the PPT courseware "Circle and the Positional Relationship of Circles", please click the circle ppt Circle and the Positional Relationship of Circles ppt tag.

"Circle and the Positional Relationship of Circles" Circle PPT Courseware 7:

"Circles and their positional relationships" Circle PPT courseware 7 Learning objectives: 1. Understand several relationships between circles and circles 2. Be able to use the positional and quantitative relationships between circles to solve problems. Key points: The five positional relationships between two circles and the quantitative relationship between the radius and center distance of the two circles.

"Circle and the Positional Relationship of Circles" Circle PPT Courseware 6:

"Circles and Positional Relationships of Circles" Circle PPT Courseware 6 Learning Objectives 1. Understand that two circles are separated from each other (external separation, internal inclusion), two circles are tangent (external tangent, inscribed), two circles intersect, and the distance between the centers of circles and other concepts. 2. Understand the positional relationship between the two circles and the quantitative relationship between d and R, r..

"Circle and the Positional Relationship of Circles" Circle PPT Courseware 5:

"Circles and the Positional Relationship of Circles" Circle PPT Courseware 5 Activity 1: Ask students to draw a circle with a radius of 5 cm on the white paper, and draw a horizontal straight line passing through its center, as shown in the picture, using the The circular template moves relative to the drawn circle along a straight line, and observe...

File Info

Update Time: 2024-10-05

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

Preview