Page 11 - Mathematics Class - IX

Unit 1 Number Systems
Number Systems

ACTIVITY 1.1

OBJECTIVE
To construct a square root spiral.

MATERIALS REQUIRED

Geometry box Pencil Plywood board Threads Nails

PRE-REQUISITE KNOWLEDGE
1. Pythagoras Theorem 2. Concept to draw a perpendicular line

THEORY
1. Number line: A line whose each point represents a real number.
p
2. Irrational numbers: The numbers which cannot be expressed in the form of , where q ≠ 0 and both p
q
and q are integers.
3. Pythagoras theorem: In a right-angled triangle,

(Hypotenuse) = (Perpendicular) + (Base) 2
2
2
PROCEDURE
1. Draw a line OX on the sheet and mark 0, 1, 2, 3... at equal distances of 1 unit using a ruler.
2. Let 0 (zero) be O and 1 be A.

3. Using compass and ruler, draw perpendicular ray at A. Name it as AY as shown in Fig. (a).
Y

O A
X´ X
0 1 2 3 4 5
Fig. (a)

4. With A as centre, mark an arc at M on AY such that OA = AM as shown in Fig. (b). Join OM.

Y
M

2

O A
X´ X
E
0 1 2 3 4 5
Fig. (b)

5. With O as centre and OM as radius, mark an arc on OX at E. Here E represents 2 .
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