Lesson Plan Guide

Georgia Learning Connections




Drawing triangles by Tennille Rushin



Students will learn to construct acute, obtuse, right, scalene, equilateral, and isosceles triangles using a protractor and GSP.


*Primary Learning Outcome:

Students will learn to identify and construct specific types of triangles.



*Assessed QCC:

QCC 13: Angle components, Angle types

Standard-Identifies the component parts of an angle, its vertex, and sides or rays; and classifies angles as acute, right, obtuse or straight



*Total Duration:

One class period: 50 minutes


*Materials and Equipment:

Geometer’s Sketchpad





Technology Connection:




  1. I will draw angles on the board and students will volunteer and name the type of angle. 5 minutes
  2. I will then ask volunteers to come to the board and draw an acute, right, and/or obtuse triangle. We will discuss what makes these triangles acute, right, and/or obtuse. 5 minutes
  3. We will talk about the specific definition for obtuse, right, and acute angles and students will write these in their notes. 5 minutes
  4. Next we will discuss how to classify triangles based on their sides. Students will learn the terms; scalene, isosceles, and equilateral. We will make connections between the angle measures and side lengths. 20 minutes
  5. Students will use GSP to construct different types of triangles. Each group will work on 2 triangles. 10 minutes
  6. Students will take a short quiz 5 minutes



The quiz will have students identify/classify the six types of triangles we focused on during class. They must also give reasons as to why they classified them like they did.



Have students find these types of triangles out in the real world. They can also draw different polygons and divide them into triangles and classify them.