"Interior Angle and Exterior Angle of Triangle" PPT courseware

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"Interior Angle and Exterior Angle of Triangle" PPT courseware

Part 1: Interior and exterior angles of a triangle

Review questions:

1. What are the interior angles of a triangle?

2. What is the relationship between the three interior angles of a triangle?

Jigsaw puzzle:

If you tear off the three interior angles of a triangle and join them together using rotation, translation, etc., what angle will you get?

Deductive reasoning:

Given △ABC, write �A+�B+�ACB=180°

Proof: Extend BC to D and make CE∥AB

∵CE∥AB

∴�A=�2

�B=�3

∵ �1+�2+�3=180°

∴ �A+�B+�ACB=180°

Interior angles and exterior angles of a triangle PPT, part 2 content: application of the theorem

Example 1 In △ABC,

Solution: ∵< A=30°,

Also ∵< A+

∴

=180°-30°-65°

=85°

Example 2 As shown in the figure,

(1)

(2)

Solution: (1) In △ABC,

∵< B=65° (found),

Also ∵

∴

(2) In △BEF,

∵< A=27°,

Also ∵

∴

Interior angles and exterior angles of triangles PPT, Part 3: Classification of triangles

Classification by sides:

Triangle: hypotenuse triangle

Isosceles triangle (isosceles, equilateral)

Classification by angle:

Triangle: acute triangle (three angles are acute angles)

Right triangle (one angle is a right angle)

Obtuse triangle (one angle is obtuse)

Keywords: Free download of Hebei Education Edition mathematics PPT courseware for seventh grade volume 2, interior and exterior angles of a triangle PPT download, .PPT format;

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"Interior and Exterior Angle of a Triangle" PPT download:

"Interior Angle and Exterior Angle of a Triangle" PPT download part one: Think about the sum of the three interior angles of a triangle. How can you verify it? Tips: Try putting the three angles together to try the verification method: such as Figure: Extend BC to CD, and make CE∥AB then...

"Interior and Exterior Angle of Triangle" PPT:

"Interior Angle and Exterior Angle of Triangle" PPT Part One Content: Review the past and learn new things 1. Related concepts of triangles: 1. What is a triangle: A figure composed of three line segments that are not on the same straight line and are connected end to end is called a triangle. 2. Vertex: Use a big...

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Update Time: 2024-07-26

This template belongs to Mathematics courseware Hebei Education Edition Seventh Grade Mathematics Volume 2 industry PPT template

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