| A | B |
|---|
| What makes two figures similar? | If corresponding angles are congruent and if the lengths of corresponding sides are in proportion |
| Scale Factor | Ratio of corresponding sides in similar figures |
| Angle Angle Similarity Postulate | If 2 anlges of a triangle are congruent to 2 angles of anoher triangle, then the triangles are similar |
| Side Angle Side Similarity Theorem | If an angle of 1 triangle is congruent to an angle of another triangle and the sides including these angles are in proportion, then the triangles are similar |
| Triangle Proportionality Theorem | If PT is parallel to QS then PQ/QR=TS/SR |
| Midsegment | Joins the midpoint of two segments |
| Midsegment Theorem | If X and Y are midpoints, then AB is parallel to XY and XY=1/2AB |
| Ratio | Comparison of 2 quantities measured in same units |
| Extended Ratio | Comparison of more than 2 quantities |
| Proportion | Compares 2 or more ratios |
| Proportion | Equation that equates 2 ratios |
| Means | Denomenator of first, numerator of second (b and c) |
| Extremes | Numerator of first, denomenator of second (a and d) |
| Cross Product Property | If a/b=c/d then ad=bc |
| Reciprocal Property | If a/b=c/d then b/a=d/c |
| Third Property | If a/b=c/d then a/c=b/d (switch the means) |
| Fourth Property | If a/b=c/d then a+b/b=c+d/d |
