Length

6.1  Length

Convert Units of Length

1 m = 100 cm

Convert 9 m 20 cm to cm.

Method:

\(9\,\text{m}\,20\,\text{cm}=\) _____ cm

\(9\,\text{m}\,20\,\text{cm}\;\Longrightarrow\;9\,\text{m}=900\text{cm} \\\quad\quad\quad\quad\;\,\Longrightarrow\;20\,\text{cm}\)

\(9\,\text{m}\,20\,\text{cm}=900\,\text{cm}\;+\;20\,\text{cm} \\\quad\quad\quad\quad\,=920\,\text{cm}\)

\(9\,\text{m}\,20\,\text{cm}=920\,\text{cm}\)

 

Addition of Length

Mathematical sentence: \(112\;\text{cm}\;+\;365\;\text{cm}\;+\;78\;\text{cm}=\) _____ cm

Method:

 \(\begin{array} {rr} \small{\color{red}{1}}\space \small{\color{red}{1}}\quad\quad\quad\, \\\space\space1\space1\space2\quad\text{cm} \\\space\space3\space6\space5\quad\text{cm} \\+\quad\space7\space8\quad\text{cm} \\\hline\space\space5\space5\space5\quad\text{cm}\\\hline \end{array}\)

 

Substraction of Length

Murud Mount, Sarawak

2 432 m

Ledang Mount, Johor

1 270 m

What is the difference in height between Murud Mount and Ledang Mount?

Mathematical sentence\(2\,432\;\text{m}\;-\;1\,270\;\text{m}=\) _____ m

Method:

\(\begin{array} {rr} \small{\color{red}{3}}\,\small{\color{red}{13}}\quad\quad\;\, \\\;2\;\cancel{4}\;\cancel{3}\;2\quad\text{m} \\-\;\;1\;2\;7\;0\quad\text{m} \\\hline\;1\;1\;6\;2\quad\text{m}\\\hline \end{array}\)

 

Multiplication of Length

The length of a terrace house is 6 m 80 cm. Find the length of 6 terrace house.

Mathematical sentence\(6\;\times\;6\,\text{m}\;80\,\text{cm}=\) _____ m _____ cm

Method:

\(\begin{array} {rr} \\6\;\text{m}\quad\quad8\;0\;\text{cm} \\\times\quad\quad\quad\quad\quad\quad6\quad\;\; \\\hline 3\;6\;\text{m}\;\quad4\;8\;0\;\text{cm} \\+\;\;\quad4\;\;\;-\;4\;0\;0\quad\;\; \\\hline 4\;0\;\text{m}\;\;\;\;\;\;\;8\;0\;\text{cm} \\\hline \end{array}\)

So, the length of 6 terrace house is 40 m 80 cm.

 

Division of Length

The overall length of the coached of a train is 14 m. Find the length of one coach.

Mathematical sentence\(14\;\text{m}\;\div\;7=\) _____ m

Method:

\(\;\;\;\;\;\,2\;\;\text{m} \\7\overline{\smash{)}1\,4\;\;\text{m}} \\\,\underline{-1\,4} \\\;\;\;\;\;\,0\)

So, the length of one coach of a train is 2 m.