Measurement
Tool used to measure angles.
Protractor
An angle less than 90°.
Acute
An angle that measures exactly 90°.
Right
The distance around a circle.
Circumference
The sum of the angles in a triangle.
180 degrees
Unit of measurement for an angle.
Degree
An angle that measures exactly 180°.
Straight
An angle between 90° and 180°.
Obtuse
The line from the center of a circle to the edge of a circle.
Radius
A triangle whose sides are all the same length.
Equilateral
Degrees for a right angle.
90 degrees
Two lines the same distance apart that never intersect.
Parallel
Two angles whose sum is 9o°.
Supplementary
The line that goes through the center of a circle from edge to edge.
Diameter
A triangle with two congruent sides.
Isosceles
Degrees for a straight angle.
180 degrees
Common endpoint where two sides of an angle meet.
Two angles that are across from each other.
Vertical
How much space is occupied by the inside of a circle.
Area
A triangle with no congruent sides.
Scalene
A word used when two angles are equal.
Congruent
Two angles that share a common side and a common vertex.
Adjacent
Two angles whose sum is 180°.
Supplementary
The circumference of a circle divided by the diameter.
Pi
Degree measurement for each angle in every equilateral triangle.
60 degrees