Reflection: Continuous Assessment Bisect Angles - Section 5: Construction: Bisect Angles


As I circulated the classroom, I listened for students’ reasoning as they tried to come up with a method for bisecting angles.  An idea came up to connect the two points on each side of the angle with a segment and to perpendicularly bisect that segment.  I decided to write up an Angle Bisector "Math Hospital" to provoke students’ talk around why making the initial arc on the angle is important (to locate two points equidistant from the vertex) and how this construction is essentially the same as the construction for a perpendicular bisector.


  Continuous Assessment: Surfacing Misconceptions
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Bisect Angles

Unit 5: Constructions
Lesson 4 of 11

Objective: Students will be able to construct angle bisectors using geometric concepts and tools.

Big Idea: Students explain the WHY behind each step of the construction to build deeper understanding of the concept of angle.

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Math, Geometry, modeling, Constructions, compass and straightedge
  80 minutes
bisect an
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