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Transparency 2. Click the mouse button or press the Space Bar to display the answers. Splash Screen. Example 2-3b. Objective. Find missing angle measures in triangles and classify triangles by their angles and sides. Example 2-3b. Vocabulary. Triangle. - PowerPoint PPT PresentationTRANSCRIPT
Click the mouse button or press the Click the mouse button or press the Space Bar to display the answers.Space Bar to display the answers.
Objective
Find missing angle measures in triangles and classify triangles by their
angles and sides
Vocabulary
Triangle
A figure formed by three line segments that intersect only at their endpoints
Vocabulary
Acute triangle
A triangle having three acute angles
Vocabulary
Obtuse triangle
A triangle having one obtuse angle
Vocabulary
Right triangle
A triangle having one right angle
Vocabulary
Scalene triangle
A triangle with no congruent sides
Vocabulary
Isosceles triangle
A triangle that has at least two congruent sides
Vocabulary
Equilateral triangle
A triangle that has three congruent sides
Example 1 Find a Missing Angle Measure
Example 2 Classify Triangles
Example 3 Classify Triangles
Find the value of x in
The sum of the 3 angles of a triangle = 1800
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Write an equation
Replace mP with 17
17
Replace mQ with 46
17 + 46
Define variable as mr
17 + 46 + mR
Bring down = 180
17 + 46 + mR = 180
Find the value of x in
Combine “like” terms
1/3
17 + 46 + mR = 180
63 Ask “what is being done to the variable”?
The variable is being added by 63
Do the inverse on both sides of the equal sign
Bring down + mR = 180
63 + mR = 180
Find the value of x in
Bring down 63
1/3
17 + 46 + mR = 180
63 63 + mR = 180
63
Subtract 63
63 - 63
Bring down + mR = 180
63 - 63 + mR = 180 Subtract 6363 - 63 + mR = 180 - 63
Combine “like” terms0 Bring down + mR =
0 + mR =
Combine “like” terms
0 + mR = 117
Find the value of x in
Use the Identity Property to add 0 + mR
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17 + 46 + mR = 180
63 63 + mR = 180
63 63 - 63 63 - 63 + mR = 180 63 - 63 + mR = 180 - 63
0 0 + mR = 0 + mR = 117
mR = 117
Add dimensional analysis
mR = 1170 Answer:
Answer: m I = 350
Find the value of x in
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Classify the triangle by its angles and its sides.
Answer: right, isosceles triangle
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B is a right angle
Angles
Right triangle
Sides
Segments AB and BC are congruent
Isosceles triangle
Classify the triangle by its angles and its sides.
Answer: acute, equilateral triangle
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Classify the triangle by its angles and its sides.
Answer: Obtuse, scalene triangle
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Q is an obtuse angle
Angles
Obtuse triangle
No sides are congruent
Sides
Scalene triangle
Classify the triangle by its angles and its sides.
Answer: right, scalene triangle
*
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Assignment
Lesson 6:2 Triangles and Angles 3 - 23 All