You didn't supply a list. The so-called rigid transformations of translation, rotation and reflection create congruent triangles.
Generally it's dilation by a factor about a point is preserves similarity but not congruency. Any transformation which includes such scalings but is otherwise rigid also preserves similarity but not congruency.
7/10-1/2 in simple form. so the two fractions have different denominators so you need to multiply both denominators 10x2 = 20 so both fractions have 20 on the bottom so they are like this now: 7/20-1/20= 6/20 simplify by 2: 6/20 divide by 2/2 =3/10. 3/10 is your answer
