Please note that dilation does not affect angles. Thus, if an image is dilated the angle remains the same and does not change.
Therefore, even if [tex] \Delta ABC [/tex] is dilated to [tex] \Delta JKL [/tex] by a factor of 1.5 (or by any factor for that matter), the linear dimensions of the original triangle [tex] \Delta ABC [/tex] will either get stretched or get shrunk by a factor of 1.5 but the angles of the original triangle will not be affected in any case.
Please note that this is true for all two dimensional geometric shapes.
