Page 94 - Start Up Mathematics_6

(d) There could be three possibilities:
 If the other end falls between C and D, then PQ < CD.

 If the other end falls exactly on D, then PQ = CD.
 If the other end falls beyond D, then PQ > CD.

Divider

P Q C D C D C D
PQ < CD PQ = CD PQ > CD
Measuring Line Segment

A line segment can be measured by:
(i) A ruler (ii) A divider and a ruler

By ruler: A ruler has centimetres marked on one side and inches on the other side. Each centimetre
mark is subdivided into 10 equal divisions. Each small division of a centimetre is called a millimetre.
Let’s learn how to measure a line segment AB.
(a) Put the ruler in such a way that its ‘0’ marking is placed on A.

(b) Now place the edge of the ruler along the line AB.
(c) Read the marking on the ruler which coincides with B. This measure gives the length of
the line segment AB. For example, the measure of the line segment AB shown below is
4 cm.

A B

By a divider and a ruler: Let’s measure the given line segment AB.

(a) Put one end of the divider at A and open the divider so
that the other end reaches B.

(b) Without disturbing the opening of the divider, put it on
the ruler in such a way that one of its ends is at ‘0’.

(c) Read the marking on the ruler where the other end of
the divider reaches.
(d) This measure is the length of line segment AB. Clearly 0
AB measures 4 cm.

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