Card Set Information
Geometry SImilarity Math
Review of Similarity for Geomtry Regents. Make sure that you have paper so that you can draw pictures.
What is a ratio?
A camparison of numbers that is a direct comparison and varies directly. 2:1 is the same as 4:2. It is always best to write these in simplest form.
What is a proportion?
An equation that involves ratios. Cross multiply these to find the answer.
What is the geometric mean?
What are other ways that you can write the proportion,
and make sure that the proportion is still equal?
Flip them (recipricol)
Diagnolly cross them
Add the denominator to the numerator.
Try this out with some numbers and check!
What is true in the angles of similar polygons?
The corresponding anlges will alway be congruent!
What is true of the sides of similar polygons?
Their corresponding sides are proportional, or all have the same ratio.
What is the sacle factor?
The ratio of the corresponding sides of a polygon.
What do you know about the perimeter of similar polygons?
The perimeter is the same proportion as the sides and the sacle factor.
What is the Angle-Angle (AA~) Similarity Postulate?
If two sides of corresponding angles are congruent, then the triangles are similar, becasue you can always figure out the last angle.
What is the Side-Side-Side (SSS~) SImilarity Theorem?
If three sets of corresponding sides are proportional, then the triangles are similar.
What is the Side-Angle-Side (SAS~) SImilarity Theorem?
If the corresponding angles between two corresponding, proportional sides are congruent, then the trianlges are similar.
What do you know about parallel lines in a traingle, such that a side and a line segment are parallel?
The two traingles are similar.
What do three parallel lines do to two transversals?
Divide them proportionally.
What does the altitude coming from the right angle in a right triangle make?
THREE similar triangles. It helps to draw all three triangles separated with their lengths if it becomes hard to see.
What is important about an altitude from the right angle?
It is creates the mean proportional, and the altitude is the geometric mean, or x. The longer part of the hypotnuse is b and the smaller part is a.