CHAPTER 21 Triangles. Types of Triangles Triangles with THREE ACUTE ANGLES are called ACUTE ANGLED triangles. Triangles with ONE OBTUSE ANGLE are called.

Slides:

Advertisements

Similar presentations

 Classify each angle as acute, obtuse or right 90 o 72 o 116 o  How do we know that angle 1 and angle 2 are congruent? 1 2.

Advertisements

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°

7/3/2015 Geometry 1 Classifying Triangles Free powerpoints at

Applying Triangle Sum Properties

ANGLES IN TRIANGLES LESSON 16(3).

10-2 Area of a Triangle 1.) What is the formula for the area of a rectangle? 2.) If a rectangle is divided into two equal triangles, what is the formula.

HOW MANY SIDES ARE THERE, AND WHAT IS THEIR ANGLE?

10.1 Triangles. Acute Triangle Not Acute Triangles.

Triangles 1 The Basics. 2 Naming Triangles For example, we can call the following triangle: Triangles are named by using its vertices. ∆ABC∆BAC ∆CAB∆CBA∆BCA.

Classify Triangles Standard 4C.

CHAPTER 23 Quadrilaterals. Special Quadrilaterals 1. Square a) All sides are the same length b) All angles are the same size (90°) c) Its diagonals bisect.

2.7 – Triangles. Type of ∆DefinitionPicture Equilateral Triangle CLASSIFICATION BY SIDES All sides are ≅

- Four sides - Four angles - Four vertices  - The diagonals are equal in length and perpendicular and bisect each other.

Triangles and Lines – Sum of the Angles in a Triangle The sum of the angles in any triangle = 180°

Angles of Triangles Chapter 4, Section 2. Angle Sum Theorem The sum of angles in a triangle is 180 o

Q: Can a triangle be formed with sides 4, 7, 9? If so, what kind? A: Median (K)

Angle and Triangle Flash Cards

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.

Angle and Triangle Flash Cards

Quarter 4 Test 3 Review LV. Basic Geometric Terms and Measuring, Drawing & Classifying Angles LVI. Polygons and Symmetry LVII. Angle Relationships LVIII.

They come in many shapes and sizes! 3 measure angles –Acute –Right –Obtuse 3 measure sides –Scalene –Isosceles –Equilateral There are 6 types of triangles.

1 An isosceles triangle has one line of symmetry.

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

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

Equilateral, Isosceles, Scalene, Right, Acute, Obtuse Types of Triangles.

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

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.

2D Computer Project By: Alexander and Alby. obtuse angle right angle 3 types of angles an angle that measure exactly 90 degrees. an angle that measure.

Copyright © Cengage Learning. All rights reserved. 12 Geometry.

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.

Warm Up 98 What is the measure of an acute angle? ____________________ What is the measure of a right angle? ____________________ What is the measure of.

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

Properties of Triangles

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.

Mathematics Types of Triangles.

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

Geometry 4.1 Triangle and Angles.

Angles of Triangles 4.2.

TRIANGLES BY ASHANTI.

Chapter 4: Congruent Triangles

Chapter 4 Section 4.1 – Part 1 Triangles and Angles.

TODAY : Triangles -Triangle notes -classifying triangle worksheet

Classifying Triangles

IDENTIFYING TRIANGLES

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

Types of Triangles.

Classifying Triangles

Classifying Triangles

Objective - To classify triangles.

Classifying Triangles

Triangles Guided Notes

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.

Types of Triangles Thursday, 11 April 2019.

Types of Triangles Thursday, 11 April 2019.

3-3 Parallel Lines & the Triangle Angle Sum Theorem

ANGLE PROPERTIES.

Triangles Teacher Twins©2014.

Triangles Teacher Twins©2014.

Classifying Triangles

Area and Perimeter Triangles.

Classifying Triangles

Presentation transcript:

CHAPTER 21 Triangles

Types of Triangles Triangles with THREE ACUTE ANGLES are called ACUTE ANGLED triangles. Triangles with ONE OBTUSE ANGLE are called OBTUSE ANGLED triangles. The sum of the INTERIOR ANGLES of a triangle is 180° 92°+37°=129° z = 180° - 129° z = 51° 37° z 92°

Exterior Angle of a Triangle The EXTERIOR ANGLES of a triangle is always equal to the sum of the two opposite INTERIOR ANGLES. x = 46° + 73° x = 119° NOTE ∆ means triangleext means EXTERIOR ANGLE means Angleint means INTERIOR ANGLE supp means SUPPLEMENTARY ANGLE 37° x 92°

Special Triangles 1. Scalene a) All sides different lengths b) All angles different sizes c) No axes of symmetry 2. Isosceles a) Two sides the same length b)Two angles the same size c) One axis of symmetry 3. Equitlateral a) Three sides the same length b) Three angles the same size (60°) c) Three axes of symmetry d) Order of rotational symmetry = 3

Drawing Triangles If you are just given the lengths of the 3 sides of the triangle you must use a pair of compasses and a ruler. If you are given the length of two sides and the size of the angle between them you must use a protractor and a ruler. Remember : always draw in pencil The PERIMETER of a triangle is the total length of its 3 sides.

Area of a Triangle The area of a TRIANGLE is calculated using the formula: Area = ½ x base x perpendicular height this is sometimes written as: Area = base x perpendicular height 2 A = ½ x b x h A = ½ x 8 x 6 A = ½ x 48 A = 24cm 2 8cm 6cm