###
intersection

point where two or more lines cross

###
equilateral

triangle with 3 equal sides

###
corresponding

angles in the same position at different points of a figure

###
protractor

tool used to draw or measure angles

###
ray

set of points that is part of a line; has an endpoint and extends

###
vertex

common point to both sides of an angle

###
acute

angle smaller than 90 degrees

###
vertical

pairs of opposite angles; have the same measure

###
right triangle

triangle with a 90 degree angle

###
supplementary

two angles whose sum of their measures is 180 degrees

###
straight

angle measuring 180 degrees

###
isosceles

two of the sides in a triangle are the same

###
equiangular

triangle with 3 equal angles, measuring 60 degrees

###
interior

angle within a polygon

###
acute triangle

a triangle with all 3 angles less than 90 degrees

###
obtuse triangle

triangle with one obtuse angle

###
obtuse

larger than 90 degrees

###
adjacent

angle that shares a vertex and a common side with another angle

###
complementary

two angles whose sum of their measures is 90 degrees

###
exterior

angle formed by extending one side of a polygon at a vertex

###
scalene

all the sides of a triangle have different lengths

###
congruent

having the same size and shape

###
similar

figures that have the same shape but not the same size

###
quadrilaterals

polygons with 4 sides and 4 angles

###
diagonal

a line that connects two vertices that are not next to each other

###
regular polygon

polygon with all equal sides and angles

### Please allow access to your computer’s microphone to use Voice Recording.

## We can’t access your microphone!

### Click the icon above to update your browser permissions and try again

Example:

### Reload the page to try again!

Reload

## Press Cmd-0 to reset your zoom

## Press Ctrl-0 to reset your zoom

### It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

## Your microphone is muted

### For help fixing this issue, see this FAQ.