Standard unit of measuring length is metre. It is denoted by the symbol $m$.
Other units of measurement are :
| millimetre | centimetre | metre | kilometre |
|---|---|---|---|
| $mm$ | $cm$ | $m$ | $km$ |
10 $mm$ = 1 $cm$
100 $cm$ = 1 $m$
1000 $m$ = 1 $km$
So smallest unit of measuring length is millimetre $mm$.
Now 10 $mm$ combines to form 1 $cm$.
Now if we add 1 $cm$ 100 times , we will get length of 1 metre .
Again if we add 1 metre 1000 times , we will get length of 1 km
Conversion of centimetre to millimetre and millimetre to centimetre
We know that 10 mm = 1 cm . i.e if we add 1 mm 10 times we will get 1 cm
i.e 1 $mm$ + 1 $mm$ + 1 $mm$ + 1 $mm$ + 1 $mm$ + 1 $mm$ + 1 $mm$ + 1 $mm$ + 1 $mm$ + 1 $mm$ = 1 $cm$ .
i.e if we multiply 1 $mm$ with 10 we get 1 $cm$.
i.e 10 $mm$ = 1 $cm$
So to convert $cm$ to $mm$ we multiply by 10 .
to convert $cm$ to $mm$ we multiply $cm$ by 10
Now we know that 1 $cm$ = 10 $mm$ .So how much is 1 $mm$ in $cm$ ??
Now consider 1 $cm$ to be divided into 10 equals parts. We have learn in the chapter fraction, that if any whole part is divided into say $n$ equal parts , then each part will be $1/n$ .
So in same way, each part is $1/10$ of 1 $cm$
But the lenth of each part is 1 mm .
So 1 $mm$ = $1/10$ of 1 $cm$
1 $mm$ = $1/10$ $cm$
to convert $mm$ to $cm$ we divide $mm$ by 10
Conversion of metre to centimetre and centimetre to metre
We know that 100 $cm$ is 1 $m$ .
So to convert metre to centimetre , we multiply $m$ by 100.
to convert metre to centimetre , we multiply $cm$ by 100
So, to convert centimetre to metre, we divide $m$ by 100.
To convert centimetre to metre, we divide $cm$ by 100.
Conversion of metre to millimetre and millimetre to metre
Conversion of kilometre to metre and metre to kilometre
We know that 1000 $m$ = 1 $km$ .
To convert $km$ to $m$, we multiply $km$ by 1000.
To convert $m$ to $km$ , we divide $m$ by 1000.
1) Convert mm to cm .
a) 45 mm .
b) 100 mm
c) 150 mm .
d) 85 mm
e) 56 mm .
Marks:
2) Convert cm to mm .
a) 4.5 cm .
b) 36 cm
c) 2 cm
d) 0.5 cm
e) 123 cm
Marks:
3) Convert cm to m .
a) 530 cm .
b) 1200 cm
c) 5000 cm
d) 25500 cm
e) 2020 cm
Marks:
4) convert m to cm .
a) 2.3 m
b) 50 m
c) 5 m
d) 21 m
e) 220 m
Marks:
5) Convert mm to m .
a) 560 mm .
b) 100 mm
c) 250 mm
d) 2530 mm
e) 1000 mm
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6) Convert m to mm .
a) 50 m
b) 450 m
c) 20 m
d) 5 m
e) 2.5 m
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7) Convert km to m .
a) 5 km
b) 2.5 km
c) 20 km
d) 29.5 km
e) 120 km
Marks:
8) Convert m to km
a) 5 m
b) 2.5 m
c) 20 m
d) 29.5 m
e) 120 m
Marks: