TRIANGLES: Angle Measures, Length of Sides and...
Transcript of TRIANGLES: Angle Measures, Length of Sides and...
TRIANGLES:
Angle Measures,Length of Sides
andClassifying
90o
45o 45o
Classifying Triangles
ClassifyingTriangles.pptx
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45o 45o
90o
**The sum of the degrees of the interior angles in a triangle is 180.
**To find the missing degrees ~ set up an equation equal to 180 and solve for the variable.
Interior Angles
60o 65o
51o
110o
88o
Calculatethedegreeoftheanglesinthetrianglesbelow.Calculatethedegreeoftheanglesinthetrianglesbelow.
Pull for the answerPull for the answer
45o 45o
90o
x x
x
x
x
x
1. 2.
3. 4.
xo
34o
Calculatethedegreeoftheanglesinthetrianglesbelow.Calculatethedegreeoftheanglesinthetrianglesbelow.
Pull for the answerPull for the answer
35o
xo
51o
x+6o
2xo
5xo
2x+7o
12o
SidesofatriangleTrytheactivitywithapartner.Whatdoyounotice?
1. Cut three pieces of straw so that their lengths are 2 inches, 4 inches, and 8 inches. Then lay them flat on a surface and try to form a triangle. Each end of the straw needs to be connected to another end of a straw. Is it possible?
2. You need three pieces of straw that are 4 inches, 5 inches and 7 inches. Then lay them flat on a surface and try to form a triangle. Each end of the straw needs to be connected to another end of a straw. Is it possible?
3. Without actually cutting them out, predict whether these three size straws would form a triangle if put together.
a. 2 in, 3 in, 5 in b. 2 in, 4 in, 5 in
c. 3 in, 4 in, 8 in d. 5 in, 5 in, 8 in
4. What can you say about the three sides of a triangle?
Sidesofatriangle
**Triangleinequalityrule**Sumofthetwosmallersidesofatrianglemustbelargerthanthethirdside.
Ex.Dothefollowingexamplescreateatriangle?1.13cm,12cm,25cm2.8ft,12ft,7ft3.9in,4in,4in
Triangle Exterior Angles
* Interior angle ~ inside the figure ~ Angle 1
*Exterior angle ~ outside the figure. It is created by extending the side ~ Angle 2
*Interior and Exterior angle at the same vertex are supplementary. ~ Angle 1 + Angle 2 = 180
2 1
interior angle
Exterior angle
109
13
58x
Example
Sidesofatriangle
Perimeteroftriangle=addallthesidesPerimeteroftriangle=addallthesides
P=64yd
26yd
P=91in2x+1
6x
6x8
Sidesofatriangle
Theratiooftheanglemeasuresinatriangleis1:3:5.Findtheanglemeasures.Thenclassifythetrianglebyitsanglemeasures.
Sidesofatriangle
Theratiooftheanglemeasuresinatriangleis11:14:20.Findtheanglemeasures.Thenclassifythetrianglebyitsanglemeasures.
Sidesofatriangle
Theratioofthesidelengthsinatriangleis4:7:9.Theperimeterofthetriangleis120feet.Findthelengthofthesides.Thenclassifythetrianglebyitssidelengths.
Sidesofatriangle
Theratioofthesidelengthsinatriangleis9:9:11.Theperimeterofthetriangleis116feet.Findthelengthofthesides.Thenclassifythetrianglebyitssidelengths.
TriangleActivities
1.Macsclasszone.comeworkbook(chapter10lesson1chapterworksheet)*countsasclassworkgrade*
2.Coloringclassifyingtriangletrees
3.Triangletoothpickscreatingandclassifyingtriangles
4.WorksheetEvennumbersonbothsidesdoinnotebooks
1. The ratio of the angle measures in a triangle is 8 : 9 : 19. Find the angle measures. Then classify the triangle by its angle measures.
2. The ratio of the side lengths of a triangle is 4 : 7 : 9. The perimeter of the triangle is 120 feet. Find the side lengths. Then classify the triangle by its side lengths.
3. The first angle is three times the second angle. The third angle is twelve less than twice the second angle. Find the angle measures. Then classify the triangle by its angle measures.
1. classzone.com2. Middle School/Math/NJ/GO3. Find textbook4. Eworkbook5. Chapter 10 Lesson 3
**Counts as a classwork grade**6. Complete Chapter 10 Lesson 27. Complete Chapter 10 Lesson 1 8. Take notebook and rotate around to each picture - answering questions in notebook.
Attachments
classifyingtriangles.ppt
ClassifyingTriangles.pptx
Classifying Triangles
Joe Griggs
Subject: Geometry
Grade Level: 7th grade
Two Ways to Classify Triangles
By Their Sides
By Their Angles
Classifying Triangles
By Their Sides
Scalene
Isosceles
Equilateral
Scalene Triangles
No sides are the same length
Isosceles Triangles
At least two sides are the same length
Equilateral Triangles
all sides are the same length
Classifying Triangles
By Their Angles
Acute
Right
Obtuse
Acute Triangles
Acute triangles have three acute angles
Right Triangles
Right triangles have one right angle
Obtuse Triangles
Obtuse triangles have one obtuse angle
Classify this triangle.
Right Scalene
Classify this triangle.
Obtuse Isosceles
Classify this triangle.
Acute Scalene
Classify this triangle.
Acute Isosceles
Classify this triangle.
Obtuse Scalene
Classify this triangle.
Right Isosceles
Triangle Degrees
The sum of the measures of any triangle is 180.
70
x
What is the measure of x?
Triangle Degrees
The sum of the measures of any triangle is 180.
45
x
What is the measure of x?
Triangle Degrees
The sum of the measures of any triangle is 180.
What is the measure of x?
x
60
50
SMART Notebook
Classifying Triangles
Two Ways to Classify Triangles
By Their Sides
By Their Angles
Classifying Triangles By Their Sides
Scalene Isosceles Equilateral
Scalene Triangles
No sides are the same length
All three angles are different measures
Isosceles Triangles
At least two sides are the same length
Two angle measures are the same
Equilateral Triangles
all sides are the same length
All three angles measure 60
Classifying Triangles By Their Angles
Acute Right Obtuse
Acute Triangles
Acute triangles have three acute angles
Right Triangles
Right triangles have exactly one right angle
Obtuse Triangles
Obtuse triangles have exactly one obtuse angle
Practice on Your Own
Classify the following triangles by their sides and angles.
Write the response on the whiteboard
1/10/2013
Geometry
11
Classify this triangle.
Right Scalene
Classify this triangle.
Obtuse Isosceles
Classify this triangle.
Acute Scalene
Classify this triangle.
Acute Isosceles
Classify this triangle.
Obtuse Scalene
Classify this triangle.
Right Isosceles
Triangle Degrees
The sum of the measures of any triangle is 180.
70
x
What is the measure of x?
Triangle Degrees
The sum of the measures of any triangle is 180.
45
x
What is the measure of x?
Triangle Degrees
The sum of the measures of any triangle is 180.
What is the measure of x?
x
60
50
SMART Notebook
Page 1: TitlePage 2: Sum of AnglesPage 3: Calculate - 1Page 4: Calculate - 1Page 5: Calculate - 2Page 6: Dec 13-11:48 AMPage 7: Dec 13-11:48 AMPage 8: Dec 14-11:25 AMPage 9: Feb 21-2:52 PMPage 10: Feb 25-10:18 AMPage 11: Jan 11-9:58 AMPage 12: Dec 13-11:48 AMPage 13: Dec 13-11:48 AMPage 14: Dec 13-11:48 AMPage 15: Dec 13-11:48 AMPage 16: Dec 13-11:48 AMPage 17: Dec 13-11:48 AMPage 18: Jan 14-12:55 PMPage 19: Dec 14-11:38 AMPage 20: Dec 14-11:38 AMPage 21: Feb 25-10:43 AMPage 22: Dec 14-11:39 AMPage 23: Dec 14-11:39 AMPage 24: Feb 20-2:54 PMAttachments Page 1