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Lesson Plan #77
Date: Monday March 31st, 2014
Class: Geometry
Topic: Basic Constructions
Aim: How can we prove why some of the basic constructions work?
Objectives:
1) Students will be able to prove why certain constructions work?
HW # 77: Cut out the triangle at right and paste onto your HW page. Construct the perpendicular bisectors of two sides of the
triangle. Locate the circumcenter. Draw in the circumcircle with you compass. Draw 3 radii of the circumcircle to the vertices of
the triangle.
Do Now:
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PROCEDURE:
Write the Aim and Do Now
Get students working!
Take attendance
Give Back HW
Collect HW
Go over the Do Now
Question: What makes the segment constructed congruent to the given segment?
Assignment #1:Online Interactive Activity:
Let’s go to http://www.mathopenref.com/constcopysegment.html
of a line segment being copied.
Assignment #2:
Assignment #3:
Construct a segment whose measure is 2𝐴𝐵
Assignment #4:
Construct the perpendicular bisector ̅̅̅̅
𝐶𝐷 of line segment ̅̅̅̅
𝐴𝐵 . What makes
̅̅̅̅
̅̅̅̅
𝐶𝐷 the perpendicular bisector of 𝐴𝐵 ?
and observe an animation of a construction
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Assignment #5: Let’s take a look at an animation of the construction of a perpendicular bisector.
http://www.mathopenref.com/constbisectline.html
Assignment #5:
Construct a line segment that is 1.5(AB)
Assignment #6:
Construct 2 perpendicular bisectors of the sides of triangle ABC.
Question:
What name do we give to the intersection of the 3 perpendicular bisectors of
the sides of a triangle?
What is the circumcenter the center of?
Assignment #7:
Construct the circumcircle of the following triangle
Question: Via construction, how could we find the midpoint of a side of a triangle?
Assignment #8:
Via construction locate the midpoints of each of the 3 sides of Triangle RPQ.
Draw in the line segment from a midpoint to the vertex opposite that midpoint?
What do we call this segment? ____________
What do we call the intersection of the 3 medians? __________
Interactive Online Activity:
http://www.mathopenref.com/trianglecentroid.html
Question #1:
Question #2:
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Assignment #9:
Assignment #10:
Assignment #11:
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