Answer:

The altitude drawn from the vertex opposite to the non-equal side bisects the non-equal side.

ABC is an isosceles triangle having equal sides AB and BC.

The altitude drawn from the vertex will bisect the opposite side.

In right triangle ABD,

Using Pythagoras theorem,

????????² = ????????² + ????????²

25² = 7² + ????????²

????????² = 625 – 49

????????² = 576

???????? = 24 cm