Math 242 – Lab 1
Basic Constructions, Measurements and Calculations
Experimenting
1) Read the Sketchpad Instructions to learn about opening and saving sketches. Open
Sketchpad and create a new sketch.
2) There are three basic elements on the tool bar of Geometer’s sketchpad: point tool, the line
tool and the circle tool. Read about these and experiment with creating objects on your
screen. Be sure you try to drag and resize your objects after you create them.
3) Read about labels and captions (there is a difference.) Experiment with creating labels on
objects and creating captions for your objects. Remember, you can turn off any label by
clicking on the object a second time.
4) For practice, review the instructions and familiarize yourself with the construction of lines,
rays, arcs and polygon interiors. These will be used in later sketches.
Creating Something
1) Create a new sketch and put your name in a caption at
the top of the sketch.
2) Create the following geometric objects on your sketch
(Each should be identified with a caption – not a label):
circle, triangle, square, non-square rectangle. Estimate
the sides and angles of the square and rectangle – if it
looks like a square that is close enough.
3) Create a line segment and label the endpoints A and B.
4) Draw two different circles with the same center. Draw
several line segments connecting the inner circle to the
outer circle. Hide both circles but not the lines.
5) Using the construct interior feature, make a triangle
with a blue interior and a square with a red interior.
Label them both. (The color will show only if you print
on a color printer.) These are different circles and
squares than the ones you made in
part 2.
Bl ue Tri angl e
Before You Print
 Make sure your name in typed in a caption box – this is a required element.
 Arrange your sketch so that it looks neat. All required elements should be clearly
labeled.
 Look in the directions to learn about print preview and how you can change
orientation of the sketch on the paper.
 Print your sketch before going on to the next part.
Lab 1 - page 1
Measurements on Your Sketch
1) Measure the length of one side of the red square and measure the area of the square.
2) Use the calculator to square the length of the side. Note: When you open the
calculator you can click on the measurement to enter it into the calculation. This
will make your calculation dynamic. Don’t just copy the number by hand. Resize
the square to see the effect.
3) Using the calculator divide the area of the square by the length of the side. Compare the
area to the length of the side. What do you expect to see?
More Construction and Calculation–
Start a new page and type your name in a caption.
4) Construct a line segment label it AB.
B
5) Construct one point on that segment and label it C.
6) Measure the lengths of AB, AC and CB. It is easier
C
to select both points and measure the distance.
7) Use the calculator to add AC and BC (make
A
dynamic calculations.) As you drag C along AB the
calculation should change with the measurements.
8) Somewhere else on the screen construct an angle and label it DEF. Measure the angle.
9) Construct another segment GE that has one end at
the vertex E and lies within the angle.
10) Measure DEG and GEF. Use the calculator to
add these measures.
11) Write paragraph that summarizes what you
D
observed in steps 4 – 11. The observation should
have something to do with measurements and
addition. Use complete sentences and be as clear
G
and complete as possible. Try to make your
E
F
observations general. Whatever you write should
be easily verified by dragging points and observing
what happens to the calculations. You may find it
helpful to look at the postulates in Section 1.3 of the
book.
As you complete the calculations and type your observations print this second sketch.
Lab 1 - page 2
A short test
Open a new sketch. Give a definition for as many of the following terms as possible. Draw a
sketch of the object near the definition. This is intended to show me how much you know.
Don’t look up the answers.
1) Line segment
2) Ray
3) Angle
4) Acute Angle
5) Obtuse Angle
6) Right Angle
7) Circle
8) Square
9) Rectangle
10) Isosceles triangle
11) Equilateral triangle
12) Right Triangle
13) Obtuse triangle
14) Rhombus
15) Trapezoid
16) Parallelogram
17) Arc
18) Sector
19) Annulus
20) Sector of Circle
What to turn in:
Three sketches with your name typed on each page.
1) The sketch from the first page.
2) The sketch and comments from the 11 steps on page 2.
3) The definitions and sketches from this page.
Lab 1 - page 3