Drawing triangles

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1. October 4, 2012
Drawing triangles and other shapes
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1. Drawing triangles

2. October 4, 2012
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The angle of 40º is called the included angle, as it lies
between the two lines of which you know the length.
A B15cm
20cm
40º
C
Sometimes you are asked to make an
accurate drawing of a sketch such as this…
You need a pencil, a protractor and a ruler.
Draw and label line A to B , using your ruler.Using a protractor, mark a point at 40º to this line.Using your ruler, draw a line from point A, through the
point at 40º.
Mark the point 20cm along this line and label it point C.Draw a line joining point B to C, using your ruler.Label the 40º angle and the line AC.
A B15cm
20cm
40º
C
Explanation

3. October 4, 2012
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The completed triangle.Draw a line longer than PQ.Measure the angle 28º at Q.
12 cm
R
P Q
28º
35º
Sometimes you are given one side and two
angles, like this…
P Q12cm
35º
R
28º
Again you need a pencil, a protractor
and a ruler.
Draw and label the line PQ.Measure the angle 35º at P.Draw the line QR.
Explanation

4. October 4, 2012
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9 cm
1
3
cm
14 cm
Construct a triangle ABC with AB = 14 cm, AC 9 cm and
BC = 13 cm.
A B
C
Explanation
You may be given the length of three sides, but no
angles.
This time you will need a pencil, a ruler and a pair of
compasses.

5. October 4, 2012
Z
You may be given two sides and a non-included
angle. That is an angle not between the two
known sides.
X Y8.6cm
60º
Z
10cm
8.6 cmX
60º
Y
10 cm
1
0

c
m
Draw the line XY.Measure the angle 60º from X.Draw a line longer than XY.Draw an arc with radius 10 cm from Y.Where the arc crosses the line is Z.Join Y to Z.The completed triangle.
Explanation
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