The perimeter of an isosceles triangle is equal to 14 cm . The lateral side is to the base in the ratio 5 : 4 the area of the triangle is?

Let lateral side = (5y) cm and base = (4y) cm
∴ perimeter = 5y + 5y + 4y = 14
⇒y = 1
So, the sides are 5 cm , 5 cm and 4 cm
Now s= 1/2 (5 + 5 + 4) cm = 7 cm
(s-a) = 2 cm
(s-b) = 2 cm and
(s-c) = 3 cm
∴ Required Area = √ (7 x 2 x 2 x 3) cm²
=2√21 cm²