A hand fan is made by stitching 10 equal size triangular strips of two different types of paper as shown in Fig. 12.28. The dimensions of equal strips are 25 cm, 25 cm and 14 cm. Find the area of each type of paper needed to make the hand fan.
Let a, b and c are the sides of triangular strips and s is
the semi-perimeter, then its area is given by:
A = 
where 
[Heron’s Formula]
= 
= 32
A= 
A = 
= 
cm2
Hence, total area of 5 Nos of triangular strips of one type = 5 × 168 = 840 cm2
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