Question

find the area of an isosceles triangle whose base is 16 cm and perimeter is 36 cm

Answer 1

the perimeter of isosceles triangle = 2a + base
36 = 2a + 16
2a+16=36
2a=36-16
2a=20
a=20/2
a=10

Answer 2

in an isosceles triangle two sides are equal therefore ,let the length of two sides be x,x
sum of length of three sides=36
16+x+x=36
16+2x=36
x=36-16/2=10
now we will draw an altitude and get a right angled triangle ,using Pythagoras theorem we get
length of altitude =6
now, area of triangle = 1/2×base ×height
=1/2×16×6=48cm×cm