Learning to use sketchpad


 

Go to the following site and download the guide which has tours to help you practice using the program.
http://www.keypress.com/sketchpad/workshop_guide.html

You will find a downloadable guide to using sketchpad at the site above.  In addition to the lessons I will be doing in class, you may want to lead yourself through the tours given on the guide.  

Located on the left-hand side of the Geometer's Sketchpad worksheet, you will see a selection of tools that can be used to draw geometrical figures.

 

	Selection Arrow: Used to select and translate an object. Click and hold mouse button to activate Rotate and Dilate tools.
	Point Tool
	Circle Tool
	Line Tool: Creates line segments. Click and hold mouse button to activate Ray and Line tools.
	Text Tool: Creates captions or label points and lines.
	Tool Box: Saves scripts for making various geometric figures

Day 1

Spend some time exploring the tools.  Start with the point tool by moving your arrow over the point box and selecting it with your mouse.  The box should be red.  Move your arrow back onto the sketchpad.  It should look like a plus sign and by clicking your mouse place a number of points on the screen.  Go back to your tools and select the arrow key.  Choose a point on your screen by left clicking with your mouse and hold down the mouse.  Drag the point to a different position on your screen. 

Skip down to the line tool box.  Click and hold the left mouse button and you will see that there are two other boxes.  We will first use the segment box, so make sure the first box is the one highlighted in red.  When you move onto the screen there should be an x this time.  Move the x to a position on your screen, left click and hold the mouse down.  Drag the x to a new position and then let go.  You should have a line segment drawn. Go up and select the arrow key again.  Move out onto the screen, left click on one of the endpoints on the segment and drag the point to make your line segment shorter or longer. 

Choose the line tool box again and this time select the ray tool.  Draw a ray by moving onto the screen, hold the left mouse down and drag in the direction you want the ray to go.  Let go.  There should be an endpoint and a point on the ray.  You will not be able to see the arrow on the screen but if you print or copy the picture into another program, the arrow appears as below

Choose the line tool box and this time choose the last box with the line shown.  Again move onto the screen, hold down the left mouse, drag and let go.  You should have a line that extends in both directions to the end of your drawing screen.  If you want your line to be horizontal, hold down the shift key as you drag and the line should snap to a horizontal position.  The same holds true for drawing a vertical line.  When you copy to another program or print, the line will have a double ended arrow as shown below.

Select the circle tool .  When you move onto the drawing screen you will see a small circle with a little plus sign in the middle.  Hold down the left mouse and drag until you have a circle. Let go and you will see a point on the circle as well as a point at the center. Use the arrow key and change the size of your circle by selecting the point on the circle, hold the left mouse down and drag the point toward the center to make it smaller and away for a larger circle.

  Select the text tool.  This can be used in two different ways.  The first is to move to the drawing screen and you will see a hand.  Hold down the left mouse and drag down and then to the right and you will see a rectangle formed.  A curser should appear in the corner of your rectangle.  You can now type text in the box.  The text box can be moved about the screen using the select key if it is in the way of any drawings.

The second way to use the hand tool is tool is to click on a point, line, ray or segment and a label will appear.  You can remove the label by clicking again on the point etc.

If you need to change the label to a different letter, double click on the label itself with the hand and a relabel box will appear.  Change the label to whatever you would like and click okay.  If the font is too small you can click on style from this box and change its size or style.

Day 2

An additional box is already shown in sketchpad 4 which  looks like the button to the left.  This is where scripts will be saved that will be used to make figures such as equilateral triangles, squares, pentagons etc.

We will be saving our tools in tool folder which is a folder already in sketchpad

The first script we will save in this box is the equilateral triangle. 

Open a new sketch and draw a circle.

Holding down the shift key select the point on the circle followed by the center.  Pull down the display menu and choose "circle by center and point"

Choose the select key and place it over the intersection of the two circles.  Click and a point should appear at the intersection

Connect the three points with segments.  The easiest method is to select all three point by holding the shift key and clicking on each point.  Press Ctrl L and three segments should appear. 

Holding the shift key click on the two circles and under display choose hide circles or press ctrl h.

The triangle remaining should be equilateral.  Using your select key, drag a rectangle around the triangle which will select all points and segments.  Under the drop down menu work, choose make script.  Under File choose save and write equi in the file name box.  Click on mytools. Okay and check to see if the equi tool is in the double arrow box. Bring up a new sketch, choose the double arrows, click on equi and practice drawing some equilateral triangles on you drawing screen.  Click and drag.

Constructing Angles

Use your ray tool and construct a ray.

Double click on the endpoint of the ray.  It should boing out at you and this means you have selected it as your center of rotation.  Use your select key and hold the shift key down.  Select the ray and the point on the ray. Pull down the transform menu and choose rotate.  Choose 75º

This angle will remain a 75 degree angle and cannot be changed in measure.

Draw another angle by constructing two rays from the same endpoint

To find the measure of your angle click first on a point on the ray, then at the vertex of the angle and then on a point on the other ray.  In the above diagram that would be B - A - C .  Under the measurement pull down menu, choose angle and you should get the measure to show up.  Go back to the angle of  75 degrees and verify that it is that measure.  On <BAC,  using your select key (arrow) drag point B and see how the measure changes as your angle gets bigger or smaller. 

In this lesson we will make a new tools (square).  We will also learn to bisect an angle, create a midpoint, construct the perpendicular bisector of a segment, make a table of values, learn to change the background,  use the parametric function and explore the tour string art.  Whew!

Lets start with the square tool.  Open up a new sketch and draw a segment.

Using your select tool double click on the endpoint A so that it boings out at you.  Select segment AB and its endpoint B and under the transform menu choose rotate 90 degrees.

Repeat the process by double clicking on the top left endpoint (C).  Select point A and segment AC and again rotate under the transform menu 90 degrees. 

Connect point D to point B using your segment tool. 

Draw a text box around the square and choose the double arrow tool to create a tool.  Be sure also to save the sketch in your tool folder. 

Midpoint of a segment.  Use your segment tool and draw a segment.  Select the segment (not endpoints and under the construct menu choose midpoint.  You can also use the control M command to do the same thing.  Rename you midpoint M.  
  
Find the length of AM and MB by selecting point A then point M and under measure choose distance.  Repeat the process to find the length of MB.  

Open up a new sketch and construct a circle.  Draw in two radii of the circle making sure to use the point already on your circle as an endpoint of one of your radii.  Connect the two points on the circle with a segment to form a triangle.

Hide your circle.  Using your select tool draw a box around the triangle to select all.  Then choose and create a new tool.  Call your tool isos.  After this save your sketch in sketchpad in the tool folder. 

Select sides of your triangle and find its length under the pull down measure menu.  Select each of the other sides and finding thier  length the same way.  Make a table by selecting the three measures and under the graph pull down menu choose tabulate.  Double click on the table and then change the size of your triangle by dragging either A or B. Do this a few times to make change the values.  Note that two of your sides always remain the same.

Select your table by clicking on it with the arrow key.  Under the edit menu choose action button and choose Hide.  A button will appear on your screen that says Hide Table.  If you click on this the table will disappear and the button will change to show table.  Click again and it should reappear. 

Altitudes of a triangle