The longest side of a triangle is four times the shortest side. The third side of the triangles is 3cm shorter than the longest side. If the perimeter of the triangle is at least 69 cm, then its :

Shortest-side ≥ 8 cm

The correct answer is Option (4) → Shortest-side ≥ 8 cm

Let the shortest side be x.

Longest side = 4x

Third side = 4x - 3

$⇒ x+4x(4x-3)≥69$

$⇒ x≥8cm$