Find the area os the shaded region in Fig. 12.12.
In 
side (AB)2 = (AD)2 + (BD)2
(AB)2 = (12)2 + (16)2
AB = 
AB = 
= 20 cm
In 
Let a, b and c are the sides of triangle and s is the semi-perimeter, then its area is given by:
A = 
where 
[Heron’s Formula]
= 
= 24
A1 = 
A1 = 
= 
cm2
In 
Let a, b and c are the sides of triangle and s is the semi-perimeter, then its area is given by:
A2 = 
where 
= 
= 60
A2 = 
A2 = 
= 
cm2
Area of shaded region is A2-A1 = 480 – 96 = 384 cm2
11