If the perimeter of an isosceles triangle is 11 cm and its base is 5cm, its area is 5/4√11cm^{2}. State true or false and give reason.
True, 2b + a = 11 ⇒ 2b + 5 = 11
⇒ 2b = 6 ⇒ b = 3
∴ Area of isosceles triangle = a/4( root under√ 4b^{2 }- a^{2 })
= 5/4 ( root under√ 4 x 3^{2 }- 5^{2}) = 5/4√11cm^{2}