In each diagram, ∆ABC has been transformed to yield ∆A'B'C'. Which transformation could NOT be achieved by rotation alone?

Question

anonymous · Answer

I think it is the first one

anonymous · Answer

I´m sorry the third one I mean

anonymous · Answer

please help

janu16 · Answer

no i say 4th one

anonymous · Answer

@Janu16 could you give me a reason please?

bobo-i-bo · Answer

It's the fifth one because the orientation of the triangles are different. If you go clockwise round one of the triange, the order in which the angles appear is the reverse of the order of the other triangle (that is, if you go clockwise round both of them). Does that make sense?

anonymous · Answer

@Bobo-i-bo so the coordinates being the same wouldn´t mean it is a rotation?

bobo-i-bo · Answer

Sorry, i don't understand. What do you mean by the coordinates being the same? I don't see any triangles with the same coordinates?

anonymous · Answer

@Bobo-i-bo I mean that, A and A` both being at -2 doesn´t mean it is a clockwise rotation?

bobo-i-bo · Answer

No it doesn't. It seems you have trouble understanding what a rotation is, would this help: https://www.mathsisfun.com/definitions/rotation.html ?

anonymous · Answer

It certainly helps, thank you so much

bobo-i-bo · Answer

Np ^_^