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MATHS202
QUADRILATERAL PROJECT
A parallelogram is a quadrilateral whose opposite sides are parallel. In this investigation you will
construct a parallelogram in GeoGebra using the definition.
Construction of a Parallelogram
Settings:
View -Turn off the Axes and the Algebra window
Options – Labeling - new points only
Decimal places – set at 1
Draw AB .
Draw a point C above segment AB .
 Construct a line though point C parallel to AB .

Segment between two points
Parallel line
Connect points A and C with the segment
tool.

Construct a line through point B parallel to AC .
Construct the intersection point D.

Hide the parallel lines and connect the points,
creating segments CD and BD .
Show / hide object
Connect the opposite vertices to create
diagonals.


Construct point E at the intersection of the
diagonals.
1) Measure the sides, diagonals (and the parts of the diagonals) and angles. Drag points A, B or C
to change the measurements. Type at least four conjectures about parallelograms directly onto
your printout. Remember, we already know the opposites sides are parallel from the definition.
Print out a copy of your work.
2) Why is it impossible to drag point D?
BSU Creative Teaching Grant 2009
Materials adapted from Exploring Geometry with The Geometer’s Sketchpad 2002; KCP
MATHS202
QUADRILATERAL PROJECT
A rectangle is an equiangular quadrilateral. In this investigation you will construct a rectangle in
GeoGebra using the definition.
Construction of a Rectangle
Settings:
View -Turn off the Axes and the Algebra window
Options – Labeling - new points only
Decimal places – set at 1
Draw AB .
Segment between two points
 Construct lines perpendicular to AB though
points A and B.
Perpendicular line
Draw a point C on the line
 through point B.
Construct a line through point C, parallel to AB .
Construct point D at the intersection.

Hide the construct lines and connect the
points, creating segments AD , DC and CB .
Show / hide object
Connect the opposite vertices to create
diagonals.



Construct point E at the intersection of the
diagonals.
1) Measure the sides and diagonals (and the parts of the diagonals). Drag points A, B or C to
change the measurements. Type at least three conjectures about rectangles directly onto your
printout. Remember that we already know all the angles in a rectangle are right angles from the
definition. Print out a copy of your work.
2) Why is it impossible to drag point D?
BSU Creative Teaching Grant 2009
Materials adapted from Exploring Geometry with The Geometer’s Sketchpad 2002; KCP
MATHS202
QUADRILATERAL PROJECT
A rhombus is an equilateral quadrilateral. In this investigation you will construct a rhombus in
GeoGebra using the definition.
Construction of a Rhombus
Settings:
View -Turn off the Axes and the Algebra window
Options – Labeling - new points only
Decimal places – set at 1
Construct a circle with center point A and point
B located on the circle.
Locate point C on circle A.
Connect the points A, B and C to form an
isosceles triangle.
Reflect point A over segment BC .
Mirror object at line
BA' and CA' .
Construct segments 
Hide circle A.
Rename point
 A’ as point
 D.
Show / hide object
Construct segment AD and label the
intersection of AD and BC point E.



1) Measure the sides, diagonals (and the parts of the diagonals) and angles. Drag point A or B to
change the measurements. Type at least four conjectures about rhombi directly onto your
printout. Remember, we already know that all sides are rhombi are congruent from the definition.
Print out a copy of your work.
2) Why is it impossible to drag point D?
BSU Creative Teaching Grant 2009
Materials adapted from Exploring Geometry with The Geometer’s Sketchpad 2002; KCP