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WHS Ch 7 Similarity
WHS Chapter 7 Similarity
Term | Definition |
---|---|
side of a polygon | one of the segments that form a polygon |
denominator | the bottom number of a fraction, which tells how many equal parts are in the whole |
numerator | the top number of a fraction, which tells how many parts of a whole are being considered |
vertex of a polygon | the intersection of two sides of a polygon |
vertical angles | two nonadjacent angles formed by two intersecting lines |
dilation | a transformation I which the lines connecting every point P with its preimage P' all intersect at a point C known as the center of dilation; a transformation that changes the size of a figure but not the shape |
scale | ratio between two corresponding measurements |
scale drawing | drawing that uses a scale to represent an object as smaller or larger than the actual object |
scale factor | multiplier used on each dimension to change one figure into a similar figure |
similar | two figures have the same shape but not necessarily the same size |
similar polygons | two polygons whose corresponding angles are congruent and whose corresponding side lengths are proportional |
similarity ratio | ratio of two corresponding linear measurements in a pair of similar figures |
similarity transformation | a dilation or a composite of one or more dilations and one or more congruence transformations |
reduction | the scale factor k in a dilation is a value between 0 and 1 |
AA Similarity Postulate | If two angles of one triangle are congruent to two angels of another triangle, then the triangles are similar |
SSS Similarity Theorem | If the three sides of one triangle are proportional to the three corresponding sides of another triangle, then the triangles are similar. |
SAS Similarity Theorem | If two sides of one triangle are proportional to two sides of another triangle and their included angels are congruent, then the triangles are similar |
Reflexive Property of Similarity | ∆ ABC ~ ∆ ABC |
Symmetric Property of Similarity | If ∆ ABC ~ ∆ DEF, then ∆ DEF ~ ∆ ABC. |
Transitive Property of Similarity | If ∆ ABC ~ ∆ DEF and ∆ DEF ~ ∆ XYZ, then ∆ ABC ~ ∆ XYZ. |
Triangle Proportionality Theorem | If a line parallel to a side of a triangle intersects the other two sides, then it divides those sides proportionally. |
indirect measurement | any method that uses formulas, similar figures, and/or proportions to measure an object |
If the similarity ratio of two similar figures is a:b , then the ratio of their perimeters is a:b , and the ratio of their areas is a²:b² or (a:b)². |