"Using Triangle Congruence to Measure Distance" Triangle PPT

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"Using Triangle Congruence to Measure Distance" Triangle PPT

Part 1: Think about it

1. What are congruent triangles?

Two triangles that completely overlap are called congruent triangles.

2. What methods have we learned to determine whether two triangles are congruent?

SSS, ASA, AAS, SAS.

3. What are the properties of two congruent triangles?

(1) The corresponding sides of congruent triangles are equal;

(2) Corresponding angles of congruent triangles are equal.

As shown in the picture, two points A and B are located at both ends of a pond. Xiao Ming wanted to use a rope to measure the distance between A and B, but the rope was not long enough. An uncle helped him come up with an idea: first pick one on the ground. Point C that directly reaches point A and point B, connect AC and extend to D, so that CD = CA; connect BC and extend to E, make CE = CB, connect DE and measure its length, the length of DE is the distance between AB distance.

Can you explain why?

Option One:

1. What are the known conditions? What's the conclusion?

In △ABC and △DEC, it is known: AB⊥BE, DE⊥BE, BE=EC, conclusion: AB=DE.

2. Can you explain the reasons for designing the plan?

Option II:

1. What are the known conditions? What's the conclusion?

In △ABC and △DEC, we know: AD//BC, AD=BC, conclusion: AB=DC.

2. Can you explain the reasons for designing the plan?

third solution:

1. What are the known conditions? What's the conclusion?

In △ABC and △DEC, we know: AD⊥BD, AD=DC, conclusion: AB=BC.

2. Can you explain the reasons for designing the plan?

Using triangle congruence to measure distance PPT, part 2: practice in class

1. As shown in the figure, connect the midpoints O of the two steel bars AA′ and BB′ together so that AA′ and BB′ can freely rotate around the point O, and a measurement workpiece is made. From the congruence of triangles, we get It is found that the length of A′B′ is equal to the width of the inner groove AB, then the reason for determining △OAB≌△OA′B′ is ( )

A. Corner B. corner corners

C． Side by side D. Jiao Jiao Bian

2. As shown in the figure, to measure the distance between two opposite points A and B on both sides of the river, first take two points C and D on the vertical line BF of AB, so that CD=BC, and then determine the vertical line DE of BF. It can be proved that △ EDC≌△ABC, we get ED=AB. Therefore, the measured length of ED is the length of AB. The reason for determining △EDC≌△ABC is ()

A.SSS B.ASA C.AAS D.SAS

3. As shown in the figure, it is known that AC=DB, AO=DO, CD=100 m, then the distance between two points A and B ( )

A. Greater than 100 m B. Equal to 100 m

C. Less than 100 m D. Unable to determine

Using triangle congruence to measure distance PPT, the third part: summary

1.Knowledge:

The purpose of using congruent triangles to measure distances is to change unmeasurable distances into measurable distances.

Basis: Properties of congruent triangles.

Key: Construct congruent triangles.

2. Method:

(1) Use the extension method to construct congruent triangles;

(2) Construct congruent triangles using the vertical method.

3. Mathematical thinking:

Establish the idea of ​​using triangle congruence to construct mathematical models to solve practical problems.

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For more information about the PPT courseware "Triangles Using Triangle Congruence to Measure Distance", please click on the Triangle PPT Using Triangle Congruence to Measure Distance PPT tag.

"Using Triangle Congruence to Measure Distances" Triangle PPT courseware download:

"Using Triangle Congruence to Measure Distances" Triangle PPT Courseware Download Part One Content: Learning Objectives 1. Be able to use the congruence of triangles to solve practical problems and understand the connection between mathematics and real life. 2. Be able to be organized in the process of solving problems Thoughts and expressions..

"Using Triangle Congruence to Measure Distance" Triangle PPT Teaching Courseware:

"Using Triangle Congruence to Measure Distances" Triangle PPT Teaching Courseware Part One Content: Learning Objectives 1. Review and summarize the judgment and properties of triangle congruence; 2. Be able to measure the distance between two points based on triangle congruence and solve practical problems in learning Key points and difficulties...

"Using Triangle Congruence to Measure Distance" Triangle PPT Download:

"Using Triangle Congruence to Measure Distances" Triangle PPT Download Part One Content: Learning Objectives 1. Be able to use the congruence of triangles to solve practical problems and understand the connection between mathematics and real life. 2. Be able to think in an organized manner in the process of solving problems and express...

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Update Time: 2024-10-19

This template belongs to Mathematics courseware Beijing Normal University Edition Seventh Grade Mathematics Volume 2 industry PPT template

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