###
vertex

The point where both rays (sides) of an angle meet.

###
equilateral triangle

A triangle in which all sides are the same length and all angles are the same size.

###
right triangle

A triangle that has a right angle. (90 degree angle)

###
obtuse triangle

A triangle in which one angle is larger than 90 degrees.

###
acute triangle

A triangle in which all three angles are less than 90 degrees.

###
isosceles triangle

A triangle in which two sides are the same length and the two base angles have the same measure.

###
scalene triangle

A triangle in which no two sides are of the same length.

###
hypotenuse

The longest side of a right triangle, opposite the right angle.

###
leg (right triangle)

The two sides of a right triangle that form the right angle.

###
base

The third side of an isosceles triangle, it may not be congruent to the other two sides.

###
leg (isosceles triangle)

The two sides of an isosceles triangle that are congruent.

###
equiangular triangle

A triangle in which the three angles are congruent.

###
adjacent sides

Sides of a triangle that share a vertex.

###
opposite side

The side across from an angle.

###
triangle

A polygon with three sides.

###
vertex angle

The angle opposite the base of an isosceles triangle.

###
180 degrees

The sum of the interior angles of a triangle.

###
base angles

The angles opposite the congruent sides of an isosceles triangle.

###
congruent triangles

Two triangles that are have the same shape and size.

### 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.