# Similar Triangles Terms

## Get down with the lingo

### Angle-Angle Postulate

A rule that says that if two triangles have two pairs of congruent, corresponding angles, then the triangles are totally BFFs—err, similar.### Center Of Dilation

Like the flame that moths just can't stay away from, the center is the point of a dilation where the rays that connect corresponding vertices of similar polygons all intersect.### Dilation

Using a scale factor to produce a new, proportional image from an original. The new shape can be bigger or smaller, but it has to be in scale. This is not to be confused with the process the optometrist uses on your pupils to blind you for 6 hours.### Enlargement

Just like setting the Xerox machine to copy at 150%, an enlargement is when your dilation results in a bigger shape than you started with. The scale factor of the dilation will be more than 1.### Image

A shape post-dilation. May or may not be grotesquely over- or under-sized.### Midsegment

A line segment that connects the midpoints of two sides of a triangle. It's half the length of and parallel to the third side.### Preimage

A shape, pre-dilation, with a predilection for preposterous predictions.### Proportion

A mathematical statement that establishes equality between two ratios. By calling themselves proportional, ratios proclaim to all that they are equivalent and deserve a nice crusty baguette just as much as the next ratio. "Liberté, égalité, geometré," as Victor Hugo so wisely wrote.### Ratio

A comparison of two quantities, written as a fraction (), with the word "to" in between (3 to 5), or with a colon (9:2). Not to be confused with*CSI: Miami's*Horatio.