Let the vertices of the △ be A,B,C & the length of smaller side BC is a.Then side AB = a+4 and side AC = 2a−6.Given the perimeter of △ ABC is 50cm.So we havea + (a+4) +(2a−6) = 50⇒ 4a − 2 = 50⇒ 4a = 52⇒ a = 13.∴ The sides are BC = a = 13cm, AB = (a+4) = 17cm and AC = (2a−6) = 20cm.Now according to Heron′s formula the area of triangle ABC with sides a, b & c is given asA = 2√[s(s−a)(s−b)(s−c)]where 2s = (a+b+c).Here a = 13cm, b = 17 , c = 20 , s = (13 + 17 + 20)2 = 502 = 25 Area of △ ABC = 2√[25 × (25 − 13)(25 − 17)(25 − 20)] = 2√(25 × 12 × 8 × 5) = 2√(5 × 5 × 6 × 2 × 8 × 5)= 2√(5 × 5 × 6 × 16 × 5) = 5 × 4 × 2√(6 × 5)= 20 2√30