Look at the smaller triangle ( these drawings should be on grid paper ), then count the dimensions of the triangle, then look at the bigger triangle. For EX: The "original diagram" would be 2 boxes in height abd 2 boxes in length, then the bigger triangle ( scale diagram ) would be 8 boxes in height and 8 boxes in length which mean the scale factor of the triangle would be 4 because 2*4 = 8 , or 8/2 = 4 . Hope this helped. :P.... Also think of it as picture over actual or big over small or visa, versa.. Which would be the dimensions of the picture drawn over the original picture or visa, versa, that would be 2/8 = 4.

Ok, so say that triangle ABC~DEF

Side A: 2 Side B: 4 Side C: 6

Side D: 4 Side E: 8 Side F: 12

Then you must write a proportion and cross multiply:

2/4 Reduce to 1/2

Then your scale factor will be 1/2.

The smaller triangle is half the size of the larger triangle

Side A: 2 Side B: 4 Side C: 6

Side D: 4 Side E: 8 Side F: 12

Then you must write a proportion and cross multiply:

2/4 Reduce to 1/2

Then your scale factor will be 1/2.

The smaller triangle is half the size of the larger triangle