Page 310 - Math Smart - 7

Constructing rectangles

You can use a ruler, a set square and a protractor to construct a rectangle.
Remember that a construction is an accurate drawing.

Example 2

Draw a sketch to help you. Draw a rectangle ABCD with length 9 cm and width 5 cm using a pencil, ruler
and protractor.
D C
J L Solution
5 cm
n r 1 5 cm
B
9 cm 9 cm
Draw a line AB that is 9 cm
long. This is the length of Draw a right angle by placing the centre
the rectangle. of the protractor at point B. Use your
ruler to measure 5 cm away from point
B. Make a mark and label it C. Line BC is
the breadth of the rectangle.

9 cm
C
+
J L
5 cm 5 cm 5 cm 5 cm

n r
9 cm 9 cm
Draw a line AD that is 5 cm long,
Join point D to point C. Label
parallel to line SC.
the sides and the corners of the
rectangle.
Example 3

Draw a sketch to help you. n
Construct rectangle PQRS that has side lengths of 40 mm and 60 mm.
Solution
j L
40 mm
Use your ruler to draw a line segment that
n r
60 mm Is 60 mm long. This is one side of the
rectangle.

Place the centre of your protractor
2 at one end of the line segment.

Measure 90° and make
a construction mark.

Place the centre of your protractor
? at the other end of the line segment

Measure 90° and make
a construction mark.

UNIT 14 I Geometrical Constructions