Question 326259
length of side = 42 
Perimeter = 3*42= 126
{{{area =sqrt(s(s-a)(s-b)(s-c))}}}
a,b,c are the sides and s= 1/2 perimeter
area = {{{sqrt(63*(63-42)(63-42)(63-42))}}}
area={{{sqrt(3*63*21)}}}
area={{{sqrt(63*63)}}}
area = 63 sq.feet