Construction - Class 9 Maths

Construction - Revision Notes - Class 9 Maths

2. Q Draw a line AB of length 8 cm and also draw its perpendicular bisector.

3. Q Draw line segment AB of 8 cm and bisect it. Further, bisect one of the gquéRparts
Sol.
Steps of Construction:

Step 1: Draw a line segment AB of length Sem using
the ruler. -

Step 3: Taking 8 as centre, draw arcs on both tl
sides of line AB, such that the radius

is same as earlier. These arcSlguld gt the
previous arcs at point And.

Step Tin BlangQ using The line PQis FO
perpeneiculár bisector of line AB. €

Step SÂWe sil difide line AC using the same method
haf was used to divide line AB.

7

4. Q Draw a circle with centre at point O and radius 5cm. Draw it's chord AB, draw the
perpendicular bisector of line segment AB. Does it pass to the center
Sol. Ans. Yes, it does.

Steps of Construction

Step 1: Draw circle with centre at point O and
radius Sem.

Step 2: Draw its chord AB,
Step 3: Now take radius more than half ab
ides

as centre, draw arcs on both the si
chord AB.

Sup Now le Ba cn nite ‘as

EP iQ respective
Step Soin P apd Q fbeipendicular bisector.
Yes, tHe pefpendicular bisector PQ of line

fent AB passes through the centre O of
He circle,

5. Q. Construction of Angle of 60, 120’, 90

60

6. Q. Construction of Angle of 60, 120,

gre

7. Arc 1, 2, 3 - Same Radius
Arc 4, 5 - Same Radius

8. Construction of Angle Bisector

Q Draw
Sol.

Steps of Construction:

Step 1:
Step 2

Step 3:

Step 4
step 5

Step A JO to P, and thus qe our angle

an angle of 72° using a protractor and then bisect it.

Draw a straight line OB using a ruler.
Using protractor draw ZAOB,
such that it is equal to 72°.
Draw an arc with O as centre, sR)
it cuts line OA and OB at points C & D.
Taking Das centre, drauf,

Faking C as centrá[ oral an arc of the same
TadiuspsuGh thet &ui the previous arc
and we get paiphP.

ctor OP.
7

9. Q Draw an angle of 30”.
Sol.
Steps of Construction:

Step 1: Draw a line segment OA.

Step 2: Taking O as centre, draw an arc of an
radius on one side of OA, such thai
intersects OA at point M

Step 3: Taking M as centre, draw an arc d
radius, such that it intersects previous
at point N.

Step 4: Join point O and N 1
Step 5: Taking N as centr# ral} an arc.

Step; Taking Migs sente ré an arc, such
Ä that iüfhtepßedtsfPrevious arc at point X.

step Toighointe O and x
+. GROB isthe required 30°angle.

10. Q. Draw an angle of 45”.

11. Q Draw an Angle of 22.5°.

Sol.
Step of Construction:

Step 1: Draw an angle AOB such that it
is 90°.

Step 2: Bisect an angle AOB such that
LCOBis 45°.

Step 3: Taking P as centre, draw an arc.

Step 4: Taking Q as centre, draw,
same radius to cut they
abpoint X.

Sté: Join xin bo 2OB=22.5°,

12. Q. Construct an angle of 15”.
15

30
60

Pé

13. Q. Draw the followjrlg angles 75°, 105°, 135”.

Sol.
Steps of Construction: s

Step 1: Construct ¿POB, such that it is w”

nl

Step 2: Construct ¿QOB, such tha
re

Step 3:Dyay an ar from GMC.

st€B 4: Keeping {hBratiius ne draw an
A arc tra pBinD” such that it cuts
lus dic at À

Step 5: yA OA. LAOBis 75°.

15. nori"

18. AG + Sen
Lato”
des cas ten

20. --

AO + Sem a
war Asem
BC+ CAs Item men
need: 20
(de adjocent he
gun aja m?)

1 Ab

2 LA, Ax

> A»:

13h)

col ue

C45

AA6C y ‘ :
4

21. ,Q Cönstrüct a triangle such that AB=5cm, ZA=60°, some of other two sides=12cm.
AG» Sem

Lae to

Be + CAs Item

22. AG» Sem
Lae to"
Be + CAs IBem

23. eel a Hm @ Consuela tangle such iat ts permet cm and woofs angles are Sand 6

0330 LAsto
fey x

x
q
2 CPE" Ade
> Age Gitechus ÑO + Pox
AN = PR
5. Tin Oh LA EC

AR A