A rotation transformation is where you turn a figure about a given point. The point about which the object is rotated can be inside the figure or anywhere outside it. There must be no change in shape or size of the object.
A reflection of an object is the 'flip' of that object over a line, called the line of reflection.
A translation is a term used in geometry to describe a function that moves an object a certain distance. The object is not altered in any other way. It is not rotated, reflected or re-sized.
All these three transformations are rigid - preserve the figure sizes.
A dilation is a transformation that changes the size of a figure. It can become larger or smaller, but the shape of the figure does not change.
Answer: dilation maps the large triangle onto the small triangle