# [05AB1E](https://github.com/Adriandmen/05AB1E), 5 bytes

    Dgtô«

[Try it online!](http://05ab1e.tryitonline.net/#code=RGd0w7TCqw&input=TG9yZW0gaXBzdW0gZG9sb3Igc2l0IGFtdAo)

    D    duplicate a (implicit input)
    g    length of a
    t    square root of a
    ô    push a split in pieces of b
    «    join by newlines (implicit output)