Find the area of the blades of the magnetic compass shown in Fig. 12.27. (Take 
= 3.32).
Let a, b and c are the sides of blade and s is
the semi-perimeter, then its area is given by:
A = 
where 
[Heron’s Formula]
= 
= 5.5
A= 
A = 
= 
cm2
Hence, total area of both the blades = 2 × 2.49 = 4.98 cm2
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