Cheatography
https://cheatography.com
Holt McDougal Geometry Unit 7
Vocabulary
Similar Polygons 
Two polygons are similar polygons if and only if their corresponding angles are congruent and their corresponding side lengths are proportional 
Similarity Ratio 
The ratio of the lengths of the corresponding sides of two similar polygons 
Similarity Transformation 
A dilation or a composite of one or more dilations and one or more congruence transformations 
Dilation 
(kx, ky) 
Indirect Measurement 
Any method of measuring that uses formulas, similar figures, and/or proportions to measure an object 
Scale Drawing 
Represents an object as smaller or larger than its actual size 
Scale 
The ratio of any length in the drawing to the corresponding actual length 
Dilation 
A transformation that changes the size of a figure but not its shape 
Scale Factor 
Describes how much the figure is enlarge or reduced 


Similar Shapes
All circles and squares are similar because they all have the same shape. 
Properties of Similarity
Reflexive 
Triangle ABC is similar to triangle ABC 
Symmetric 
If triangles ABC is similar to DEF, then triangle DEF is similar to triangle ABC 
Transitive 
If triangle ABC is similar to DEF and triangle DEF is similar to XYZ, then triangle ABC is similar to triangle XYZ 


Theorems & Postulates
AngleAngle (AA) Similarity Postulate 
If two angles of one triangle are congruent to two angles of another triangle, then the triangles are similar 
SideSideSide (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 
AideAngleSide (SAS) Similarity 
If two sides of one triangle are proportional to two sides of another triangle and their included angles are congruent, then the triangles are similar 
Triangle Proportionality Theorem 
If a line parallel to a side of a triangle intersects the other two sides, then it divides those sides proportionally 
Converse of the Triangle Proportionality Theorem 
If a line divides two sides of a triangle proportionally, then it is parallel to the third side 
TwoTransversal Proportionality 
If three or more parallel lines intersect two transversals, then they divide the transversals proportionally 
Triangle Angle Bisector Theorem 
An angle bisector of a triangle divides the opposite sides into two segments whose lengths are proportional to the lengths of the other two sides 
Proportional Perimeters and Areas Theorem 
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 a^{2}/b^{2} 

Created By
Metadata
Comments
No comments yet. Add yours below!
Add a Comment
Related Cheat Sheets
More Cheat Sheets by CCRoses