Lesson Plan : Pattern Block

Sum of the Interior Angles

NJCCS
4.3 A Patterns and Algebra Algebra 1
3. Identify and determine the sum of interior angles
Entry Skills:
Students should be familiar with the definitions of a regular polygon and sum of the interior angles of a triangle.

Strategies Utilized for Achieving Objectives
• Direct Instruction
• Modeling
• Guided Practice
• Independent Practice
• Cooperative Learning

Materials: paper, pen/pencil, protractor pattern blocks (triangle, hexagon, square and protractor), a worksheet of various polygons.


Introduction:
Students will be giving various polygons(triangle, square, hexagon) . Using the protractor students will determine the number of degrees for each angle of each pattern block. Give the students the regular polygons and have them draw triangles extending from one vertex (defined as a point of intersection between two edges of a polygon).

Procedure:
• Ask the students “How many degrees are in any triangle?”
• Have the students come up with a conclusion about how many degrees are in each regular polygon based on the number of triangles they were able to draw
• Have the students come up with a relationship between the number of sides of the polygon and how many triangles they were able to draw from one vertex
• Come up with a generalization/formula (n-2)
• Build on the formula based on how many degrees are in each triangle 180(n-2)
• Ask how many angles are in each regular polygon and complete the formula



Follow Up Discussion:
A group discussion will occur following the 5 minute exercise. Students will be asked to verbalize their solutions and show their chart on the board or on the overhead.

Assessment:
Assessment and understanding will be based on participation in the activity and class discussion. Students will be worksheet on various polygons and determine the degree of measurement.