Grade 7 Unit 7 Geometry Glossary Flashcards

A set of vocabulary flashcards covering geometry terms, including angle relationships and properties of 3-D solids, based on the Grade 7 Unit 7 curriculum.

Adjacent angles

Angles that share a side and a vertex; for example, a $75^{\circ}$ angle and a $15^{\circ}$ angle placed next to each other.

Base (of a pyramid or prism)

The face of a pyramid or prism that gives the solid its name; a prism has two identical parallel bases, while a pyramid has one base.

Complementary angles

Two angles whose measures add up to $90^{\circ}$, such as a $65^{\circ}$ angle and a $25^{\circ}$ angle.

Cross section

The shape you see when you slice through a 3-D figure; for instance, slicing a rectangular pyramid parallel to the base results in a smaller rectangle.

Face

Each flat side of a polyhedron; for example, a cube has $6$ faces which are all squares.

Identical copy

A copy of a figure that has the same shape and size as the original.

Polygon

A closed 2-D shape with straight sides that do not cross each other.

Prism

A solid with two bases that are identical copies; the base of a prism gives the solid its name.

Pyramid

A solid in which the base is a polygon and all of the other faces are triangles that meet at a single vertex.

Radius

A line segment that connects the center of a circle with a point on the circle; every radius of a circle is the same length.

Right angle

An angle whose measure is $90^{\circ}$.

Straight angle

An angle that forms a straight line and measures $180^{\circ}$.

Supplementary angles

Two angles whose measures add up to $180^{\circ}$; for example, a $75^{\circ}$ angle and a $105^{\circ}$ angle.

Surface area

The number of square units needed to cover all the faces of a polyhedron, without any gaps or overlaps.

Vertex

A corner or a point where two or more lines or rays meet; an angle is named based on its vertex.

Vertical angles

Angles that are opposite each other when two lines cross; vertical angles have the same measure.

Volume

The number of cubic units that fill a 3-D region without any gaps or overlaps.