Hi!
Assuming that you're in class X.
Use this theorem: If two triangles are similar, then the ratio of the area of both triangles is proportional to the square of the ratio of their corresponding sides.
So if the original triangle's sides are x,y and z.......the sides of the new triangle formed are 2x,2y and 2z.
Thus, the ratio of their corresponding sides becomes 1/2 and hence our final answer will be (1/2)2= 1/4
Hope you've understood this question. All the best for your boards!!