Page 72 - Maths Class 06

IV. Comparison by using divider A B P Q
Open the divider and place the
two ends of the divider on A and B
respectively. Carefully lift it and
place one end on P and the other
end along PQ. Compare
ABand PQ.

The best way to measure a line segment is to use divider and
ruler both. Open the divider and place its two ends on A and
B respectively to measure AB. Carefully lift the divider and
place one end on zero of graduated ruler and read the
corresponding reading of the other end from the ruler. This
reading gives the length of AB. A B A B

EXAMPLE 1. Draw a line segment AB = 6 cm. Mark a point C on AB, lying between A and B. Verify
AB = AC + CB.
SOLUTION :
A C B

6 cm A C
C.M. 1 2 3 4 5 6
Draw AB = 6 cm. Mark any point C that lies on AB. 6 5 4

Using the ruler, measure AC CB, and AB.
AC = 2 cm, BC = 4 cm and AB = 6 cm.
C B
Clearly, AB = AC + CB = 4 + 2 = 6 cm C.M. 1 2 3 4 5 6
6 5 4
Hence, verified AB = AC + CB.

EX AM PLE 2. Given AB = 8 cm. Mark a point C, the midpoint of AB. Now, mark a point D, the midpoint of
CA. Find the length of DB.

SOLUTION : Draw AB = 8 cm us ing a ruler. Place the zero 2 cm 4 cm
mark of ruler on A and mark a point C at a
A D C B
distance of 4 cm from A as C is midpoint of
AB = 8 cm. 8 cm

As, AC = 4 cm, D the midpoint of AC, will be at a distance of 2 cm from A.
Again, using the ruler, mark 2 cm from A along AB and name it D.

Using scale, measure DB = 6 cm.

Exercise 5.1

1
1. Draw PQ = 9 cm. Mark a point R such that PR = PQ. Verify that PR = RQ by measurement.
2

Mathematics-6 72