Geometry Vocab Words

By:Kamya Pentakota

adjacent angles

meaning- when they have a common side and a common vertex and don’t overlap

alternate exterior angles

meaning- when two lines crossed which is called transversal they need to be the opposite sides of the transversal

alternate interior angles

meaning- on opposite sides of the transversal but its inside the two lines.

complementary angles

when two angles add up to 90 degrees

corresponding angles

the two parallel lines are crossed over by a transversal thats when the two angles are matching from there same sides.

supplementary angles

when two angles add up to 180 degrees.

parallel lines

when two lines are the same distance apart and will never intersect.

perpendicular lines

when two lines that intersect each other create right angles.

transversal line

a line that crosses two parallel lines.

vertical angles

angles that are opposite from each other when two lines intersect.


the distance around a flat object (polygon). you can find the perimeter by adding all the sides up.


the amount of space inside a flat object (polygon).

surface area

the total or the sum of faces from a 3D object.


the amount of space in a 3D object or shape.


the distance around a circle.


a line that cuts through the center of a circle.


a line that is 1/2 of a diameter.


a flat surface, typically outside surface of a 3D object.


a line that connects faces together, it is a line where two faces meet.


a point where two or more straight lines meet (corner).