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Classic Constructions. Ryan Caliguri – WMHS Jeffrey Wainz - WMHS. G.SR.07.02. G- Geometry SR- Spatial Reasoning and geometric modeling 07- 7 th grade curriculum 02- The second type of concept in that section. G.SR.07.02. Terminology Informal justifications. G.SR.07.02.
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Classic Constructions Ryan Caliguri – WMHS Jeffrey Wainz - WMHS
G.SR.07.02 G- Geometry SR- Spatial Reasoning and geometric modeling 07- 7th grade curriculum 02- The second type of concept in that section
G.SR.07.02 Terminology Informal justifications
G.SR.07.02 • Basic Geometric Constructions • Perpendicular Bisector • Equilateral Triangle • Angle Bisector • Inscribed Circle • Circumscribed Circle
Terminology Compass: an adjustable device used to construct circles Straight Edge: any tool that is used to draw straight lines during constructions
Terminology Bisector: line that divides a segment or angle into two equal halves Perpendicular: lines that intersect at 90 degree angles
Terminology Equilateral Triangle: triangle with 3 congruent sides and angles Circumscribed Circle: a circle drawn around a triangle
Terminology Vertex: the point where two lines intersect to form an angle Inscribed Circle: a circle drawn inside of a triangle
Terminology Line: a figure that goes on forever in 2 directions Line Segment: a line with a defined length
Terminology Ray: a figure that goes on forever in one direction and ends in a point on the other Radius: a line that goes from the center of the circle to the outside
Perpendicular Bisectors Cuts a line in half New line is perpendicular to the original segment
Angle Bisectors Cuts an angle in half Two new created angles are congruent
Equilateral Triangle A triangle with sides of exactly the same side All angles are 60 degrees
Inscribed Circle Creates a circle using angle bisectors The circle touches all three sides of the triangle
Inscribed Circle Prerequisites Angle bisectors Perpendicular lines through a point
Circumscribed Circle Creates a circle using perpendicular bisectors The circle touches the vertexes of the triangle
Where will this be used? Architectural design Surveying Crafts
Where is all of this used? http://www.clker.com/clipart-25627.html
Conclusion Tools: Compass Straightedge Pencil
Conclusion Angles and lines can be bisected with Circles Lines Points
Work Cited http://www.daviddarling.info/encyclopedia/C/compasses.html http://www.theofficedealer.com/ACM45012-Westcott-45012-Shatter-proof-Ruler.html http://inefalon.info/staedtler- 55600-comfort-compass-set.php http://www.clker.com/clipart- 25627.html MMSTC
Works Cited https://commons.wikimedia.org/wiki/File:Green_equilateral_triangle_point_up.svg http://en.wikipedia.org/wiki/Circumscribed_circle http://www.mathwords.com/i/inscribed_circle.htm
The Game! 2 players Whoever says the correct letter first wins- click “Answer” to get the correct answer Correct answers receive one point unless otherwise specified MMSTC
Question 1 An angle is given, what is the first step in making it’s bisector? ( Where does the circle get placed?) Go To Diagram!!!
A B C What’s the answer?
Answer A
Question 2 When two lines intersect, and a circle has been constructed, radiating from the intersection point, where does the compass needle go for the next step? Go To Diagram!!! MMSTC
C A B What’s the answer?
Answer C
Question 3 Once one circle is constructed on the first circle’s intersection with the angle’s line, how big should you make the next one and where should it go? Go To Diagram!!!
4” A C B 8” 4” 4” What’s the answer?
Answer B
Question 4 When making a perpendicular bisector, where would you place the first circle? Go To Diagram!!!
A B C What’s the answer?
Answer A
Question 5 After one circle has been created, beginning the creation of a perpendicular bisector, what would be the next step? Go To Diagram!!!
A B C What’s the answer?
Answer B
Question 6 With two circles constructed, of equal size over both ends of the segment, what is the next construction to be made? Go To Diagram!!!
A B C What’s the answer?
Answer A
Question 7 When creating an equilateral triangle, what is the first construction made on a segment? Go To Diagram!!!
A B C What’s the answer?