Question

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

Answer 1

Diagonal will form a right angle& isosceles triangle include 2 sides of square and the diagonal since every side of square is equal

sin a=perpendicular/hypotenuse

sin 45=perpendicular(p)/10

$\bf \frac{1}{2}^{1/2} =p/10$

$\bf \frac{10}{2^(1/2)}=p$

$\bf Area\: of \:square \:= side^2$

$\bf Area = (\frac {10}{2^{1/2}}) × (\frac {10}{2^{1/2}})$

$\bf Area = \frac{100}{2}$

$\bf Area = 50cm^2$