Creer acertado

[poli]

Is this a common way of saying to believe it's right?

[chileno]

Yes. :)

[AngelicaDeAlquezar]

Not so common, but not so unusual, and yes, that's the meaning. :D

[sosia]

Agree. It's not so common , but i'ts usually used when it refers to "behaviour"
-No me parece acertado que vayas con esa ropa a un funeral
-No creo acertado que tu hija se case con ese hombre
-No creo que la política del presidente sea la más acertada.
saludos :D