The sides of a quadrilateral field, taken in order are 26 m, 27 m, 7 m, 24 m respectively. The angle contained by the last two sides is a right angle. Find its area.
Here the length of the sides of the quadrilateral is given as
AB = 26 m, BC = 27 m, CD = 7 m, DA = 24 m
Diagonal AC is joined.
Now, in triangle ADC
By applying Pythagoras theorem
$A C^{2}=A D^{2}+C D^{2}$
$A C^{2}=14^{2}+7^{2}$
AC = 25 m
Now area of triangle ABC
Perimeter = 2s = AB + BC + CA
2s = 26 m + 27 m + 25 m
s = 39 m
By using Heron's Formula
The area of a triangle $=\sqrt{s \times(s-a) \times(s-b) \times(s-c)}$
$=\sqrt{39 \times(39-26) \times(39-27) \times(39-25)}$
$=291.84 \mathrm{~m}^{2}$
Thuc the area of a trianglo ic $201 \mathrm{~g} 4 \mathrm{~m}^{2}$
Now for area of triangle ADC
Perimeter = 2S = AD + CD + AC
= 25 m + 24 m + 7 m
S = 28 m
By using Heron's Formula
The area of a triangle $=\sqrt{s \times(s-a) \times(s-b) \times(s-c)}$
$=\sqrt{28 \times(28-24) \times(28-7) \times(28-25)}$
$=84 \mathrm{~m}^{2}$
Thus, the area of a triangle is $84 \mathrm{~m}^{2}$
Therefore, Area of rectangular field ABCD
= Area of triangle ABC + Area of triangle ADC
= 291.84 + 84
$=375.8 \mathrm{~m}^{2}$
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