Another way to prove triangles are similar is by SSS, side-side-side. If the measures of corresponding sides are known, then their proportionality can be calculated. If all three pairs are in proportion, then the triangles are similar.
put 3 into 15 than put 6 into 15 then the answer u get from putting 6 into 15 subtract that by 2 and the answer u get from the u multpy the answer that u got from putting 3 into 15 together