Question

find the area and perimeter of a square whose diagonal is 10 cm long

Answer 1

p of a sq= 4*side
4*10
40cm

area of a sq= side*side
10*10
100cm2

Answer 2

We know AREA=1/2 (diagonal)^2 
then,area=1/2(10)^2
              =1/2  X 100 =50cm^2
perimeter of a square=2 root 2 X diagonal 
                                =2 root 2 X 10
                                =20 root 2 cm