SUBJECT: Geometry

GRADE: High School

TECHNOLOGY: Geometery’s Sketchpad
BY: Judy Cho

TRIANGLES

Target Grade/Subject: Geometry Class of 24 students. They will be in a group of 4 working together in a team.

Objective: For the students to discover that in a triangle, one side can not be longer than the sum of the other two sides. They will be able to make various types of triangles with different lengths using the worksheet and discover the lengths of triangles.


Materials: Computers. Sketch pad or a similar program. Worksheet of the lengths of triangles.


Lesson Description:

Go over last night’s homework. (20 min)

Students will define and draw couple of triangles on their own. I will go around the room checking their answers giving them positive reinforcements. Then, as a class, we will brainstorm a definition together and have some of the students put their examples on the board. (20min)

Pass out the computer lab “Lengths of triangles” worksheet to each of the students and an extra one per group. The students will play around with the computer, allow it for a little bit but not extensive. Explain to them that they must try to make couple of the triangles with the given lengths and draw them. If they can not draw certain triangles, explain why. Do the bottom of the worksheet where you must create some of your own 5 different triangles and print in out. Everyone write on their own worksheet for the record and fill out an extra one to turn in. (30 min)

Collect the group worksheet and go back to the classroom. Get back in to the large group and write on the transparency what they found out. Explain to them why the sum of any two sides of the triangle must exceed the third side. (20 min)

Give them homework.


Evaluation Procedure
As the students are defining the definition of a triangle, I move around the classroom to check their understanding.
When the students are at the computers, I walk around to check if they are on task and if they are getting the concept.
I collect the group worksheets to see if they understood the lesson. When we are back in the classroom, they come up with what they learned. Homework will also be assigned to see if they understand the concept.