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Lesson Plan
Grade: 10th-12th

Geometry Standard:
PS3

Name: Kyle Ostlie
Subject: Geometry
Students are able to determine, prove, and apply triangle congruence, triangle
similarity, and the sum of angles property for triangles. G.3.A, G.3.B
NETS student standard:
4. Critical Thinking, Problem Solving, and Decision Making Students use critical thinking skills to
plan and conduct research, manage projects, solve problems, and make informed decisions using
appropriate digital tools and resources. Students:
c. collect and analze data to identify solutions and/or make informed decisions.
6. Technology Operations and Concepts Students demonstrate a sound understanding of technology
concepts, systems, and operations. Students:
a. understand and use technology systems

Objective: Students will use Geometer’s Sketchpad to determine that SSS, SAS,
ASA, and AAS all guarantee congruent triangles. While SSA and AAA do not.
Students will then apply their findings to creating

Anticipatory Set: Students will take a 3 question, multiple-choice pre-assessment
on how to construct congruent angles and line segments. Students will log their
answers using the ActiVotes so I can see which students may need more support
during the activity.

Lesson:
o Students will get their assigned Netbooks from the cart, log onto their
account, and navigate to my website to download the Geometer’s
Sketchpad activity file.
o After opening the file, students will create triangles using 3 angles (AAA),
3 sides (SSS), 2 sides and 1 angle (SAS and SSA), and 2 angles and 1 side
(ASA and AAS). I will circulate throughout the room and check in with
students that struggled with the pre-assessment.
o Students will compare the triangles they created with triangles other
students created in their table group. They are to determine which sets of
information guaranteed congruent triangles. They will record the findings
of their group and be prepared to share with the class.
o One person from each group will be randomly called on to share out the
group’s findings with the rest of the class. We will come to a class
decision about which

Closure: Students will get out their notes and record the congruent triangle
shortcuts SSS, SAS, ASA, and AAS along with example diagrams.

Materials Needed:
o ActivBoard with ActiVote Flipchart
o Class set of Netbooks with Geometer’s Sketchpad Software.
o Geometer’s Sketchpad “Congruent Triangle Investigation” file.