Page 12 - Mathematics Class - IX

6. Draw MZ perpendicular to OM and mark an arc on it such that MN is 1 unit as shown in Fig. (c).

Z
N

Y
M
3
2

E
O A
X´ X
2
0 1 2 3 4 5
Fig. (c)

7. Join ON. Similarly continue step 6 to get spiral up to 10 as shown in Fig. (d)

P 1
1 N
Q
1
1 4 3 M

R 5 2 1
1 6
A
O 1
S 7

1
8
T
9
1
10
U
1
V
Fig. (d)
OBSERVATIONS
On actual measurement, we get
OM = .................... ON = .................... OP = ....................
OQ = .................... OR = .................... OS = ....................

OT = .................... OU = .................... OV = ....................

INFERENCE
A beautiful square root spiral is obtained.

EXTENDED TASK
1. Use plywood board, thread and nails to make a spiral like this and showcase it in your class.
2. Make a journal on real life applications of square root spiral.

APPLICATION
We can illustrate the existence of irrational numbers using this activity.

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