Students learn about classifying angles by their measure.
Objectives
Upon completion of this lesson, students will:
have learned what determines whether an angle is acute, obtuse, or right
Standards Addressed:
3rd Grade
Geometry
The student will demonstrate through the mathematical processes an understanding of the connection between the identification of basic attributes and the classification of two-dimensional shapes.
4th grade
Geometry
Standard 4-4: The student will demonstrate through the mathematical processes an understanding of the relationship between two- and three-dimensional shapes, the use of transformations to determine congruency, and the representation of location and movement within the first quadrant of a coordinate system.
Standard 4-4: The student will demonstrate through the mathematical processes an understanding of the relationship between two- and three-dimensional shapes, the use of transformations to determine congruency, and the representation of location and moveme
Measurement
Standard 4-5: The student will demonstrate through the mathematical processes an understanding of elapsed time; conversions within the U.S. Customary System; and accurate, efficient, and generalizable methods of determining area.
Student Prerequisites
Technological: Students must be able to:
perform basic mouse manipulations such as point, click and drag
use a browser for experimenting with the activities
Teacher Preparation
The teacher will need:
access to a browser
Key Terms
acute angle
An angle whose measure is less than 90 degrees
obtuse angle
An angle whose measure is greater than 90 degrees
right angle
An angle of 90 degrees
Lesson Outline
Focus and Review
Review any previously learned information regarding angles.
Objectives
Let the students know what they will be doing and learning today. Say something like this:
Today, class, we are going to learn about angles.
We are going to learn about ways to classify angles:
Acute Angle
Obtuse Angle
Right Angle
Teacher Input
Lead the class in a short
discussion about angles.
Guided Practice
Open the
Angles applet, show the students how it works, and emphasize that they can ignore the "Two angles are"
drop-down menu.
Ask students to point out which angles are acute, obtuse, and right.
Show the
Angles Worksheet to students and explain that they are supposed to write the names of all the angles that are
acute in the acute column, etc.