Name__________________________________________
Geometer’s Sketchpad Introductory activity.
Part I. Introduction
1) Left menu is used to draw lines, points, circles, and for selecting. The pointer should be selected when
you want to select objects in your drawing.
 If an object is highlighted in pink, then it is selected.
 To deselect everything (objects that are highlighted in pink), select pointer and click in any blank
space.
2) Draw a ray, line, and segment.
 Why do the ray and line extend off the page?______________________________________
 Whey doesn’t the segment extend off the page?____________________________________
3) Draw points, circles, text
4) If you’re having difficulties, always check if something is highlighted in pink. This means it is selected.
It is advisable to choose the pointer and select a blank spot to deselect everything after every step!
Part II. Exploring Constructions with Geometer’s Sketchpad
A. Construct
1) Draw a segment. (Deselect when done)
2) Double click each endpoint and label as A and B.
3) Construct the perpendicular bisector.
a. Select segment
b. From menu: Construct>midpoint (or Ctrl-M). Label as point “C”
c. Select segment and endpoints.
d. Menu: Construct > perpendicular line
e. Draw a point on the line (not on AB) and label the point as “D”.
4) Show the measure of angle DCA and angle DCB.
5) Drag an endpoint A or B what do you notice about the measure of angle DCA?
_____________________________
PRINT your drawing to turn in.
B. Draw – do not delete part A drawing.
1) Draw a segment that does not overlap with previous drawing.
2) Draw a point on the segment (should highlight in blue)
3) Label the endpoints as E,F, and the new point as G.
4) Select the points E,G. From menu: Measure>distance
a. The distance will highlight pink in the left. Deselect by selecting background.
5) Repeat step 4 for G and F.
6) Try to move G with pointer, until EG = FG. What is G? _________________
7) Draw a line through G. Label new point on line as H.
8) Select E,G,H. From menu: Measure>angle.
9) Drag H until the angle is 90 degrees. What is the line GH? ________________
PRINT your drawing to turn in.
Investigate: Compare your “Construction” with your “Drawing”.
1. Drag A and B, observe AC,CB, m<DCA. Is DC always the perpendicular bisector of AB no matter how
you manipulate the figure?
2. Drag E and F. Observe EG, GF, and m<HGF. How is the relationship between EF and HG different
than part 1?