Which type of transformation uses a scale factor?

translation
reflection
rotation
dilation

Translation moves the object so that doesn't use a scale factor, a reflection is the same shape but in the opposite form so that doesn't use a scale factor, a rotation rotates the shape so that uses rotational symmetry so that won't work so diliation is the enlargement of the shape so that uses a scale factor

so the answer to your question is diliation

Dilation type of transformation uses a scale factor, Because when you use a scale factor, you multiply all the sides by some factor. In a dilation, the sides get bigger.