Directions for GSP Necessary Constructions

Directions for GSP Necessary Constructions

A.Draw Polygons

Select the segment tool
Hold and drag a segment
To draw another side, put the segment tool on one of the endpoints of the first segment (the endpoint will turn blue).
The hold and drag the next segment.
Continue until the polygon is finished, making sure it is a closed figure.

B.Labeling

Any point or line can be labeled. Points are labeled with capital letters, starting with A, and lines are labeled with small letters, beginning with j.

To label either a point or a line:
Choose the labeling tool. The arrow should become a hand.
Move the hand over the point or line you want labeled. You will know it is in the right spot because the hand will turn black.
Click on the point or line.
If you would like a different letter or label that the default, double click on the labeled point or line. A box will appear on your screen which will allow you to change the label.

C.Hiding Objects

To hide an object:
Select the object(s) that you want to hide.
Go to Display and you will see "Hide ______" under the first horizontal line. Select "Hide ______." (I left a space after "Hide" because it will change based on what you have selected to hide).

D.Measuring Side Lengths and Angles

To measure a side length:
Highlight a line segment.
Go to Measure and select Length.
The measurement will appear in centimeters on the screen
If the line segment is not already labeled, measuring it will also label it according to the default.

Look closely at the angle you want to measure. There should be three points on your angle, two that are on the rays (or endpoints of segments) and one should be the vertex of the angle.
VERY IMPORTANT: The vertex of the angle needs to be selected second.
Three points need to be selected to measure an angle. You can select them in any order as long as the vertex is selected second.
Once the points are highlighted, go to Measure and chose Angle.
The angle measurement will appear in degrees on the screen.
If the angle is not already labeled, measuring it will also label it according to the default.

E.Preference Features

Go to the Edit menu and select Preferences at the bottom of the menu.
On the Units tab, you can select different types of units and precision.
For example, if you needed to measure a segment length in inches, you would go to this box first and change the Distance unit. You can also change the precision, meaning that you could measure an angle to three or four decimal places if necessary.

F.Construct Perpendicular and Parallel Lines

To construct a perpendicular line:
Draw the line or segment that you want in the construction or use one that is already on the screen.
Create a point either on the line or segment, or put a point out in space (on the white screen).
Select that point (the point you want the perpendicular through) and the line or segment you want it perpendicular to.
Go to the Construct menu and choose Perpendicular.

G.Construct Polygon Interiors and Measure Area

In order to measure the area of a polygon, the interior must be constructed. In other words, the interior of the polygon will be colored.

To construct the polygon interior:
Draw a polygon (see section A if you need guidance).
Select the vertices of the polygon in order.
Go to the Construct menu and choose "______Interior." (I left a space in front of "Interior" because that word will change based on the type of polygon that you drew.)
The polygon should now have a colored interior. Yellow is the default color. See if you can change the color.

Select the colored interior of the polygon whose area you are interested in.
Go to Measure and choose Area.
The polygons area will appear on the screen
If the vertices of the polygon were not already labeled, calculating the area will also label the vertices.

H.Constructing Points on Objects and Intersections

Draw an object (a polygon, a line, a circle…)
Select the object you want the point on.
Go to Construct and choose "Point on ______." )I left a space after "Point on" because the word will change depending on what object you have selected.)

An intersection can be created in two ways. However, for both ways, the GSP only understands the intersection of 2 lines or segments, not 3 lines or segments.

Method 1:

Method 2: