"Rule and Compass Drawing" PPT courseware

Description

"Rule and Compass Drawing" PPT courseware

Basic knowledge review

1. The tools for drawing with ruler and compass are ruler and compass.

2. We have learned to use a ruler and compass to draw a line segment equal to a known line segment and an angle equal to a known angle.

3. As shown in the figure, draw the bisector of ∠B, the height on the BC side, and the midline on the AB side (there is no limit to the drawing tools)

Review introduction

Known: ∠AOB, find ∠A′O′B′, so that ∠A′O′B′=∠AOB

Methods and tips:

Then ∠A′O′B′ is the angle sought

Find the three sides of a triangle and find the triangle

Known: line segments a, b, c

Find: △ABC, let BC=a, AC=b, AB=c

(1) Make line segment BC=a,

(2) Draw an arc with C as the center and b as the radius.

(3) Draw an arc with B as the center and C as the radius.

The two arcs intersect at point A

(4) Connect AB, AC

Then △ABC is the triangle you want to construct

Given the two sides of a triangle and the angle between them, find the triangle

Known: line segment a, b, ∠α, find: △ABC, let BC= a,

AB＝c，∠ABC＝∠α

practice

(1) As ∠MBN＝ ∠α

(2) Intercept BC = a on ray B M, intercept BA = b on ray B N,

(3) Connect AC

Then △ABC is the triangle you want to construct

Expansion exercises

As shown in the figure, in ABC, BC=5 cm, AC=3 cm, AB=3.5 cm, ∠B=36°, ∠C=44°. Please select the appropriate data and draw a triangle congruent with △ABC. (Use three methods to draw a picture, do not write the method, but mark the data used from the triangle drawn)

practise

1. The only triangle that cannot be made using a ruler and compass is ( )

A. Three known sides B. Two known sides and the angle between them

C. Two angles and the included side are known. D. Two sides and the opposite angle of one of them are known.

2. The right triangle that cannot be made using a ruler and compass is ( )

A. The hypotenuse and a right-angled side are known. B. Two right-angled sides are known.

C. Two acute angles are known. D. One acute angle and a right side are known.

3. Which triangle can be constructed with the following line segments as sides ( )

A. 2 cm, 3 cm, 5 cm B. 4 cm, 4 cm, 9 cm

C. 1 cm, 2 cm, 3 cm D. 2 cm, 3 cm, 4 cm

Keywords: teaching courseware for drawing with ruler and compass, Qingdao edition eighth grade mathematics volume PPT courseware download, eighth grade mathematics slide courseware download, downloading PPT courseware for drawing with ruler and compass, .PPT format;

For more information about the "Rule and Compass Drawing" PPT courseware, please click on the Rule and Compass Drawing ppt tab.

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Update Time: 2024-11-20

This template belongs to Mathematics courseware Qingdao Edition Eighth Grade Mathematics Volume 1 industry PPT template

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