Geometry Vocabulary Part 3

Major arc

arc whose measure is greater than a semi-circle or 180 degrees

Central angle of a circle

Angle whose vertex is the center of the circle and whose rays are radii of the circle.

Congruent arcs

arcs with equal measure in the same circle or in congruent circles.

Inscribed angles

angle whose vertex is on the circle and whose sides are chords of the circle.

Bases

Congruent polygons lying in parallel planes.

Altitude

Segment joining the two base planes and perpendicular to both.

Lateral faces

faces of a prism that are not its bases.

Lateral area

Sum of the area of its lateral faces.

Lateral edges

Intersection of adjacent lateral faces.

Surface area

Sum of the area of all its faces.

Right prism

Is a prism whose lateral faces are rectangles

Oblique prism

Is a prism whose lateral faces are parallelograms.

Cube

Is a prism where all sides are squares.

Triangular prism

Is a prism whose parallel faces (the bases) are congruent triangles.

Cylinder

Has two congruent circular bases in parallel planes.

Cone

Has a vertex and a circular base.

Line of symmetry

Divides a figure into two congruent halves that reflect each other.

Perimeter

Of a polygon is the distance around the polygon.

Area

Of any surface is the number of square units required to cover the surface

Volume

Of a 3 dimensional figure is the number of cubic units contained in the solid.

Circumference

The distance around a circle

Conditional statement

a statement that can be written in an if-then form.

Hypothesis

In a conditional statement the statement that immediately follows the word if.

Conclusion

In a conditional statement the statement that immediately follows the word then.

Converse

The statement formed by exchanging the hypothesis and the conclusion of a conditional statement.

Inverse

The statement formed by negating both the hypothesis and the conclusion of a conditional statement.

Contrapositive

The statement formed by negating both the hypothesis and conclusion of the converse of a conditional statement.

Biconditional

The conjunction of a conditional statement and its converse.

Deductive reasoning

A system of reasoning that uses facts, rules, definitions, or properties to reach logical conclusions.

Inductive reasoning

Reasoning that uses a number of specific examples to arrive at a plausible prediction.