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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
Date:
Lesson 8
Solve for Unknown Angles—Angles in a Triangle
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
DO NOW:
Find the measure of angle x in the figure to the right.
Explain your calculations. (Hint: Draw an auxiliary line segment.)
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
Discussion
The sum of the 3 angle measures of any triangle is
.
In any triangle, the measure of the exterior angle is equal to the sum of the measures
of the
angles.
These are sometimes known as _________________________ angles.
Base angles of an
Each angle of an
__________
triangle are equal in measure.
__________ triangle has a measure equal to 60°.
Relevant Vocabulary
Isosceles Triangle: An isosceles triangle is a triangle with at least two sides of equal length.
Equilateral Triangle: An equilateral triangle is a triangle with three sides of equal length.
DRAW:
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
Exercises
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Find the measure of angle ‘a’ in the figure to the right. Justify your results.
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
In each figure, determine the measures of the unknown (labeled) angles.
Give reasons for your calculations.
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
Geometry M1L8 HW Solve for Unknown Angles in Triangles
Find the unknown (labeled) angle in each figure. Justify your calculations.
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
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Geo M1L8 Solve for Unknown Angles in Triangles 9­12­16 P.4.notebook September 14, 2016
Challenge Problem:
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