A scale is a ratio between the model and the actual representation.
A scale factor is the number used when finding how much a figure was enlarged by or reduced by. The easiest way to find it is to find two corresponding sides and find their simplified ratio.
Similar figures must meet 3 rules in order to be considered similar figures.
1) Must be the same shape and have corresponding sides with the same properties
2) Must have the same/corresponding angles from one shape to the other
3) Must be proportionate (scale factor is the same for all corresponding sides)
Corresponding sides are outlined below by color coding the sides that correspond. Notice that they have the same properties in relation to their respective triangles.
Classwork Similar figures (1-8)
Notes and Practice
1/6 HW: Similar figures (9-16)