Question

Find area of a isosceles triangle whose perimeter is 11cm and base 5cm

Answer 1

let equal sides be x
2x+5=11
2x= 6
x=3
hieght²=hypotenuse ²- base²
hieght²=9-6.25
hieght=√3.75 = 1.936
area= 1/2*(5*1.936) = 4.84m^2

Answer 2

perimeter of an isosceles triangle is given by
                                                                            2a+b
which is equal to 11 cm
one side base is equal to 5cm
now, 
       2a + b = 11
      2 a + 5 = 11
            2 a = 11 - 5
           2 a = 6
           a = 3
are by Heron's Formula

s= a + b + c/2, = 5.5
area= sqare root of 5.5*.5*2.5*2.5=4.145