Lesson 3-3: Triangles Vocab: Equiangular Acute triangle Right triangle Obtuse triangle Equilateral triangle Isosceles triangle Scalene triangle Exterior.

Slides:

Advertisements

Similar presentations

TODAY IN GEOMETRY…  STATs on Ch. 3 Test  Learning Target: 4.1 Classify Triangles and find measures of their angles  Independent Practice.

Advertisements

Draw the following: 1. acute triangle 2.right triangle 3.obtuse triangle 4. acute, scalene triangle 5.obtuse, isosceles triangle 6. right, scalene.

Triangles. A triangle is a polygon with three sides.

DO NOW 1) X = 180 2) 55 + X = 180 3) X + 58 = 90 4) 31 + X = 90.

4.1 Triangles and Angles.

Blue – 2/23/2015 Gold – 2/24/ Name 2 pair of alternate interior angles  5 &  3 and  4 &  1 2. What is the sum of m  1 + m  2 + m  3? 180°

Applying Triangle Sum Properties

Classify Triangles Standard 4C.

Chapter 4 Congruent Triangles. 4.1 & 4.6 Triangles and Angles Triangle: a figure formed by three segments joining three noncollinear points. Classification.

Triangles Review.

Classifying Triangles Angle Measures of Triangles.

Warmup – grab a book Room , submit answers for x and y.

Triangles Part 1 The sum of the angles in a triangle is always equal to: 180°

3-3 Parallel Lines & the Triangle Angle Sum Theorem M11.B B Objectives: 1) To classify triangles and find the measures of their angles. 2) To.

Section 3-4: Parallel Lines and the Triangle Angle-Sum Theorem.

Objectives: Classify triangles and find the measures of their angles Use the exterior angles of triangles.

4.1 & 4.2 A Notes. Type of ∆DefinitionPicture Equilateral Triangle CLASSIFICATION BY SIDES All sides are 

Triangle A polygon with three sides and three angles. A triangle can be names by its’ side lengths and angles. – Side lengths: isosceles, equilateral,

Triangle Classification. Objectives Classify triangles by their angle and side measures Find the sum of the measure of the interior and exterior angles.

Classify triangles by sides No congruent sides Scalene triangle At least two sides congruent Isosceles triangle Three congruent sides Equilateral triangle.

Goal, to classify triangles by their sides and by their angles.

4-1 Triangles and Angles. Theorem 4.1: Triangle Sum The sum of the measures of the interior angles of a triangle is 180 . xx yy zz  x +

TRIANGLES AND TYPES OF TRIANGLES. A triangle has three sides.

What is a triangle A plane figure, created by connecting three points that are not in the same line. Three – side polygon whose angles add up to 180°

4.1 Classifying Triangles. Objectives  Identify and classify triangles by angles  Identify and classify triangles by sides.

4.1 Apply Triangle Sum Properties. Objectives  Identify and classify triangles by angles or sides  Apply the Angle Sum Theorem  Apply the Exterior.

Classifying Triangles Classifying by Angles: Acute - 3 acute angles Obtuse - 1 obtuse angle Right - 1 right angle Equiangular – An acute triangle with.

Perpendicular Lines, Parallel Lines and the Triangle Angle- Sum Theorem.

Geometry Section 4.1 Triangle Sum Theorem. A triangle is the figure formed by three line segments joining three noncollinear points. A B C.

Find the value of x. 1. x + 2x + 3x = 180 6x = x + x + 40 = x + (x + 1) + 35 = x + 40 = 180 x = 70 3x + 36 = x = 48.

Classifying Triangles How many degrees can be found in all triangles? 180 We can classify triangles 2 ways: By their angles By their sides.

Triangles and Angles Classifying Triangles. Triangle Classification by Sides Equilateral 3 congruent sides Isosceles 2 congruent sides Scalene No congruent.

Classifying Triangles Lesson Classifying by Angle Acute triangles have three acute angles. Obtuse triangles have one obtuse angle. Right triangles.

Lesson 4-1 Classifying Triangles. 5-Minute Check on Chapter 3 Transparency 4-1 Refer to the figure. 1. What is the special name given to the pair of angles.

Classifying Triangles. Two Ways to Classify Triangles  By Their Sides  By Their Angles.

Scalene triangle: A scalene triangle is a triangle that has no equal sides. The following is a scalene triangle.

Lesson 8.3 Concept: How to classify triangles by their sides and angles. An equilateral triangle has three sides of the same length. An isosceles triangle.

Triangles Chapter What is the sum of the angles inside a triangle? 180º? Prove it m Given A B C Angle Addition Postulate/Definition of a Straight.

Activity You can find the sum of the angle measures in a triangle. Triangles Cut a triangle from the corner of a piece of paper. Label the corners.

Classify These Triangles by Sides and Angles. Chapter 4 Congruent Triangles Section 4.1: Triangle Sum Properties Todays Objective: Determine if a right.

4.1 Triangle Angle Sum and Properties. How many degrees in a triangle? The sum of the angles in any triangle is exactly 180 degrees.

Applying Triangle Sum Properties

Mathematics Types of Triangles.

Warm Up 5-1 Classify each angle as acute, obtuse, or right

4.1 Apply Triangle Sum Properties

Geometry 4.1 Triangle and Angles.

Bellwork Classify each angle as acute, obtuse, or right. 90° 72° 116°

Section 3-4 Angles of a Triangle.

Triangles & Their Angles

Chapter 4: Congruent Triangles

Lesson 3: Parallel Lines and the Triangle Angle-Sum Theorem

Types of Triangles.

Objectives -triangle names -remote interior -exterior

Classifying Triangles

Objective - To classify triangles.

Triangles Guided Notes

Add up all the sides Perimeter of Area of a Rectangle: ANY polygon:

Lesson 5-1 Angles of Triangles.

Classifying Triangles

Drill 1) x = 180, solve for x 2) How many degrees do the interior angles of a triangle add up to. 3) What type of triangle has an angle that.

Triangles & Angles.

3-3 Parallel Lines & the Triangle Angle Sum Theorem

Lesson 3: Introduction to Triangles

4.1 – Apply triangle sum properties

Triangles Lesson 10-4.

Classifying Triangles

Presentation transcript:

Lesson 3-3: Triangles Vocab: Equiangular Acute triangle Right triangle Obtuse triangle Equilateral triangle Isosceles triangle Scalene triangle Exterior angle

Angle Sum Theorem The sum of the measures of a triangle is A B C “The measure of angle A plus the measure of angle B plus the measure of angle C equals 180”

Classify by angles Type of triangle PropertyDrawing AcuteAll angles < 90 0 ObtuseOne angle > 90 0 RightOne angle = 90 0

Classify by sides Type of triangle PropertyDrawing ScaleneNo sides = Isosceles 2 or more sides are = Equilateral3 sides =

Hints & suggestions What are the other angles in a… –Obtuse triangle: –Right triangle: Classify using angles & sides –Draw a right, isosceles triangle (use markings!) May have to use the distance formula Acute and add to 90 Acute

Exterior Angle Theorem ► An exterior angle is formed by extending a side outside the triangle Exterior angle Theorem: The measure of an exterior angle is equal to the sum of its remote interior angles. Remote interior angles A B CX And don’t forget…

Example 1-2c Identify the indicated triangles in the figure. a. isosceles triangles b. scalene triangles Answer:  ABC,  EBC,  DEB,  DCE,  ADC,  ABD Answer:  ADE,  ABE

Example 1-4c Find the measures of the sides of  ABC. Classify the triangle by sides. Answer: ; since all 3 sides have different lengths,  ABC is scalene.

Find all the missing angles b c d e Use Exterior angles Triangle Sum Supplementary angles