Unit Geometry Basics Vocabulary

Vocabulary flashcards covering foundational geometry concepts, angle relationships, distance, midpoint, perimeter, circumference, and area based on unit lecture notes.

Intersection

The set of points two or more figures have in common.

Ray

Part of a line that consists of one endpoint and all the points of the line on one side of the endpoint.

Segment

Part of a line that consists of two endpoints and all points between them.

Collinear Points

Points that lie on the same line.

Supplementary Angles

Two angles whose measures have a sum of $180$.

Complementary Angles

Two angles whose measures have a sum of $90$.

Vertical Angles

Two angles whose sides are opposite rays.

Adjacent Angles

Two angles that share a side but do not overlap.

Angle Bisector

A ray that divides one angle into two angles with the same measure.

Perimeter

The sum of the lengths of the sides of a polygon, or the distance around a polygon.

Radius

The distance from the center to a point on a circle.

Diameter

The distance across a circle, through the center.

Area

The number of square units a figure encloses.

Circumference

The distance around a circle.

Triangle

A polygon with three sides.

Quadrilateral

A polygon with four sides.

Distance Formula

A formula used to calculate the distance between two points on the coordinate plane: $d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}$.

Midpoint Formula

A formula used to find the middle point of a segment on the coordinate plane: $\left(\frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2}\right)$.

Area Addition Postulate (Postulate 1-10)

States that the area of a region is the sum of the areas of its nonoverlapping parts.