Question

The dashed triangle is a dilation image of the solid triangle with the center at the origin. Is the dilation an enlargement or a reduction? Find the scale factor of the dilation.
graph

Answer 1

The easiest place to calculate the scale factor would be either a completely horizontal or vertical line (in your case, the rightmost edge of the triangle)

The dilation is a reduction of the solid triangle, since it is getting smaller. The length of the rightmost edge of the solid triangle is 9, while the dashed triangle is only 3. Therefore, the scale factor is by 1/3

Answer 2

You could also check the coordinates of each point on the triangle. If you multiply a coordinate pair on the big triangle by 1/3, it should equal the coordinate pair on the smaller triangle.