Find in square metres the area of a triangle whose (a) base $ =8 \mathrm{~cm}, $ altitude $ =6 \mathrm{~cm} $ (b) base $ =38000 \mathrm{~mm} $, altitude $ =4500 \mathrm{~mm} $
Given:
The measures of a triangle are:
(a) base \( =8 \mathrm{~cm}, \) altitude \( =6 \mathrm{~cm} \) (b) base \( =38000 \mathrm{~mm} \), altitude \( =4500 \mathrm{~mm} \)
To do:
We have to find the areas of the triangles in square metres.Solution:
We know that,
Area of a triangle of base $b$ and altitude $h$ is $\frac{1}{2}bh$. $1\ m=100\ cm$
$1\ cm=10\ mm$
Therefore,
(a) base \( =8 \mathrm{~cm} \)
$=\frac{8}{100}\ m$
altitude \( =6 \mathrm{~cm} \)
$=\frac{6}{100}\ m$
Area of the triangle $=\frac{1}{2}\times\frac{8}{100}\times\frac{6}{100}\ m^2$
$=\frac{24}{10000}\ m^2$
$=0.0024\ m^2$
(b) base \( =38000 \mathrm{~mm} \)
$=\frac{38000}{10}\ cm$
$=3800\ cm$
$=\frac{3800}{100}\ m$
$=38\ m$
altitude \( =4500 \mathrm{~mm} \)
$=\frac{4500}{10}\ cm$
$=450\ cm$
$=\frac{450}{100}\ m$
$=4.5\ m$
Area of the triangle $=\frac{1}{2}\times38\times4.5\ m^2$
$=19\times4.5\ m^2$
$=85.5\ m^2$
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