Question

find the are of isosceles triangle if the perimeter is 11 cm and base is 5 cm

Answer 1

let ABC be an isosceles triangle.
given ,
perimeter of the isosceles triangle=11cm
semi perimeter=11cm/2
base BC=5cm
now,
perimeter=11cm
AB+BC+CA=11cm
AB+5cm+CA=11cm
AB+CA=11cm-5cm
AB+AB=6 cm(ABC is an isosceles triangle)
2AB=6cm
AB=6cm/2
AB=3cm=CA
therefore area of the issosceles triangle
=√s(s-a)(s-b)(s-c)
=√11/2(11/2-3)(11/2-5)(11/2-3)cm^4
=√11/2x5x1x5 cm^2
=5x√11/2x1 cm^2
=5√11/2cm^2
=5√5.5cm^2
hope it's the required answer...