Learning how to draw polygons is a step toward drawing tessellations using LogoWriter. Included in this activity are some polygons that do not lend themselves to tessellating, however, that is something the students can discover.

Objectives: [NCTM Standards Grades 6-8: Algebra, Geometry, Communication, Reasoning and Proof]

1. To use the software, LogoWriter, to draw

square
triangle
pentagon
hexagon
octagon
rectangle

2. To learn how to draw polygons with variable sides by writing procedures in LogoWriter.

Materials

1. Computer
2. LogoWriter software

Procedure:

[It is assumed that the basics of LogoWriter have already been introduced.]

1. Instruct the students to make a new page.
2. Remind the students that they know how to

draw straight line segments
turn the turtle to the right
turn the turtle to the left

3. Challenge the students to use this knowledge to draw a square.
4. Check for the methods used. Possibilities include:

square -

fd 50 rt 90
fd 50 rt 90
fd 50 rt 90
fd 50 rt 90

OR

repeat 4[fd 50 rt 90]

5. Challenge the students to draw the other polygons. Possibilities include:

triangle -

fd 50 rt 120
fd 50 rt 120
fd 50 rt 120

OR

repeat 3[fd 50 rt 120]

pentagon -

fd 50 rt 72
fd 50 rt 72
fd 50 rt 72
fd 50 rt 72
fd 50 rt 72

OR

repeat 5[fd 50 rt 72]

hexagon -

fd 50 rt 60
fd 50 rt 60
fd 50 rt 60
fd 50 rt 60
fd 50 rt 60
fd 50 rt 60

OR

repeat 6[fd 50 rt 60]

octagon -

fd 50 rt 45
fd 50 rt 45
fd 50 rt 45
fd 50 rt 45
fd 50 rt 45
fd 50 rt 45
fd 50 rt 45
fd 50 rt 45

OR

repeat 8[fd 50 rt 45]

rectangle -

fd 50 rt 90
fd 70 rt 90
fd 50 rt 90
fd 70 rt 90

OR

repeat 2[fd 50 rt 90 fd 70 rt 90]

6. Instruct the students to go to the "flip side" and write procedures for the various polygons. Encourage them to write procedures just by adding a "to ____" to the beginning of the procedure and an "end". For example:

TO SQUARE
fd 50 rt 90
fd 50 rt 90
fd 50 rt 90
fd 50 rt 90
END

or they might write

TO SQUARE
repeat 4[fd 50 rt 90]
END

Sample Procedures

Introduce the idea of a variable. Introduce one possible procedure and encourage the students to develop procedures using variables for all of the polygons. These are possible procedures:

to square :side
repeat 4[fd :side rt 90]
end

to triangle :side
repeat 3[fd :side rt 120]
end

to pentagon :side
repeat 5[fd :side rt 72]
end

to hexagon :side
repeat 6[fd :side rt 60]
end

to octagon :side
repeat 8[fd :side rt 45]
end

to rectangle :width :length
repeat 2[fd :width rt 90 :length rt 90]
end