22 terms

angle

A figure that is formed by two rays or two line segments with a common endpoint

acute angle

An angle with a measure of less than 90 degrees.

obtuse angle

An angle with a measure of more than 90 degrees but less than 180 degrees.

straight angle

An angle with a measure of exactly 180 degrees.

right angle

An angle with a measure of exactly 90 degrees.

reflex angle

An angle with a measure of more than 180 degrees but less than 360 degrees.

vertex

The point where the rays of an angle or the sides of a polygon meet.

adjacent angles

Two angles with a common side and vertex that do not otherwise overlap

arc

A part of a circle between and including two endpoints of the circle.

census

An official count of population and the recoding of other demographic data such as age, gender, income, and education.

congruent

Figures having the same size angles, side lengths, and shape.

diameter

A line segment that passes through the center of a circle or sphere and has endpoints on the circle or sphere

equilateral triangle

A triangle with all three sides equal in length. Each angle measures 60 degrees.

isosceles triangle

A triangle with at least two sides equal in length. Angles opposite the congruent sides are congruent to each other.

pentagon

A 5-sided polygon.

perimeter

The distance around the boundary of a 2-dimensional figure. The perimeter of a circle is called its circumference.

radius

A line segment from the center of a circle or sphere to any point on the circle or sphere.

regular polygon

A polygon in which all sides are the same length and all angels have the same measure.

scalene triangle

A triangle with sides of three different lengths. The 3 angles have different measures.

vertical (or opposite) angles

When two lines intersect, the angles that do not share a common side. They have the same measure.

interior angle

Angles inside of a polygon.

intersect

The point where two lines meet or cross