Basic geometrical constructions
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Transcript of Basic geometrical constructions
SMPK PENABUR GS
BASIC GEOMETRICAL CONSTRUCTIONS
Constructing a 900 Angle
Step 1Draw a line with the measure is 5 cm
5 cm
Constructing a 900 Angle
Step 2Draw point A at the line
A
Constructing a 900 Angle
Step 3Place the point of the compass at A and draw an arc that passes through the line at point P and Q
P QA
Constructing a 900 Angle
Step 4Place the point of the compass at P and draw an arc that passes through Q
P QA
Constructing a 900 Angle
Step 5Place the point of the compass at Q and draw an arc that passes through P that cuts the arc drawn in Step 4 at R.
P QA
R
Constructing a 900 Angle
Step 6By using ruler, joint A to R, so angle RAQ is 900
P QA
R
900
Constructing a 600 Angle
Step 1Draw the arm PQ.
P Q
Constructing a 600 Angle
Step 2 Place the point of the compass at P and draw an arc that passes through Q.
P Q
Constructing a 600 Angle
Step 3Place the point of the compass at Q and draw an arc that passes through P. Let this arc cut the arc drawn in Step 2 at R.
P Q
R
Constructing a 600 Angle
Step 4 Join P to R. The angle QPR is 60o
P Q
R
600
Constructing a 300 Angle
We know that, x 600 = 300
So, to construct an angle of 30º, first construct a 60º angle and then bisect it.
Constructing a 300 Angle
Step 1 Construct 600 angle
P Q
R
600
Constructing a 300 Angle
Step 2 With the point of the compass at P , draw an arc intersecting arm PQ at M and intersecting arm PR at N.
P Q
R
600
M
N
Constructing a 300 Angle
Step 3 At point M and N draw an arc with same radius then intersect at point T
P Q
R
600
M
N
T
Constructing a 300 Angle
Step 4 Join P to T. Then angle TPQ is 300
P Q
R
600
M
N
T
300
Your TurnConstruct the angle below by using compass and ruler :a. 450
b. 22,5c. 150
d. 67,50
e. 52,50
Constructing a 450 angle
We know that,
x 900 = 450
So, to construct an angle of 45º, first construct a 90º angle and then bisect it.
Constructing a 450 angle
Step 1Construct 900 angle
P Q
R
Constructing a 450 angle
Step 2Put your Compass at the point P, and draw an arc intersect PQ and PR at A and B.
P Q
R
A
B
Constructing a 450 angle
Step 3Put your Compass at the point A and B then draw an arc with the same radius so intersect each other at the point C
P Q
R
A
B
C
Constructing a 450 angle
Step 4Joint P to C, so angle CPQ is 450
P Q
R
A
B
C
450