congruent

figures with same size and shape

corresponding parts

a pair of sides or angles in the same position on similar figures

reflectional symmetry

when a figure can be folded on a given line that divides it into two congruent parts

reflection

a flip across a given line

rotation

a turn around a given point with a given angle and direction

rotational symmetry

when a figure can be turned around a central point less than 360 degrees and it matches up with the original image

transformation

a change in the size or position of a figure

translation

movement of a figure along a straight line

similar figures

have the same shape but are not the same size

scale factor

a ratio used to enlarge or reduce similar figures

dilation

a transformation that changes the size of an image but not the shape.

ratio

a comparison of two numbers by division

proportion

an equation that states that two ratios are equal

rate

a ratio of two quantities with different units

enlargement

an increase in size of all dimensions in the same proportions and have a scale factor > 1

reduction

a decrease in size of all dimensions in the same proportion and have a scale factor < 1

unit rate

a rate simplified so the denominator is 1 (mpg, cost/item)

cross products

used to solve proportions or compare two ratios

indirect measurement

uses similar figures and proportions to find a missing measurement

scale

the ratio of a distance in a drawing to the actual distance