Can this question be solved by finding the coordinates of D and E using section formula? (ratios of the areas are equal to the ratio of the squares of corresponding sides- seems new and out of ncert, though i understand it)

Hi Divya,

 

Yes it can be done in that way too. And it is not new dear. That theorem has been done in SA1. Similarity of triangles pg 141 NCERT, Areas of Similar triangles.

 

You could use either theorem. Your marks will not be cut since this is a valid theorem taught in SA1.

 

You can find the coordinates of D and E using Section formula. Then you can find the area of triangle ADE and ABC using the area formula.

And then find the ratio.