The area of a circle whose radius is the diagonal of a square whose area is 4 sq. units is :

Solution (By Examveda Team)

Area of square = 4 sq.units
Side of square = $$\sqrt 4 $$ = 2 units
Diagonal of square = $$2\sqrt 2 $$ units
Radius of the circle = $$2\sqrt 2 $$ units
Radius of the circle :
$$\eqalign{ & = \pi {r^2} \cr & = \pi \times {\left( {2\sqrt 2 } \right)^2} \cr & = 8\pi \,\text{sq. units} \cr} $$