scale factor is the new size ÷ original size.
82÷73.8= 1.1recurring
92÷82.8=1.1recurring
so if going from smaller to larger triangle, scale factor is 1.1recurring.
if going FROM the bigger triangle TO the smaller triangle, it is the opposite way:
73.8÷82=0.9
82.8÷92=0.9
so this would be the scale factor...it all depends on which is the original image.