Find the area of an isosceles triangle each of whose equal sides measures 13cm and whose base measures 20cm.

Let,

a = 13 cm

b = 13 cm

And,

C = 20 cm

Now,

s =

=

= = 23 cm

We know that,

Area of triangle =

=

=

= 10

= 10 × 8.306

= 83.06 cm²

Therefore,

Area of isosceles triangle = 83.06 cm²