Question

find the area of an isoceles triangle whose equal sides are 12 cm each and the perimeter is 30cm

Answer 1

area of the triangle with given sides is
$9 \sqrt{15 \: \:}$
cm^2

Answer 2

if each equal side is 12 cm 

let the unequal side is x 

30 = 12+12+x

30-24 = x

6=x

then the other side is 6cm 

then, semi perimeter = 30/2=15cm

area by heron's fromula

area = root {15*(15-12)(15-12)(15-6)}

area =root {15*3*3*9}

area = 3*3 *root 15

area = 9root15