30 terms

perimeter

the distance around a polygon

polygon

a closed figure formed by 3 or more line segments that intersect only at their endpoints

regular polygon

a polygon with equal sides

area

the number of square units needed to cover a given surface

parallelogram

a quadrilateral with 2 pairs of parallel sides

rectangle

a parallelogram with four right angles

triangle

a 3-sided polygon

center

the point inside a circle that is the same distance from all points on the circle

chord

a line segment with both endpoints on the circle

circle

the set of all points in a plane that are the same distance from a given point called the center

circumference

the distance around a circle

diameter

a line segment that passes through the center of a circle and has endpoints on the circle, or the length of that segment

pi (n)

the ratio of the circumference of a circle to the length of its diameter; π ≈ 3.14 or

radius

a line segment with one endpoint at the center of a circle and the other endpoint on the circle, or the length of that segment

area

the measurement inside the circle

circumference

the measurement around the outside of a circle

pi

the ratio of the circumference of a circle to the length of its diameter; π ≈ 3.14 or 22/7

acute angle

measures less than 90°

acute triangle

a triangle with only acute angles

angle

two rays meet at an endpoint

complementary angle

two angles whose measures have a sum of 90°

equilateral triangle

a triangle whose all sides are equal

isosceles triangle

a triangle with at least two congruent sides

obtuse angle

measures more than 90°

obtuse triangle

a triangle with one obtuse angle

right angle

measures exactly 90°

right triangle

a triangle with one right angle

scalene triangle

a triangle with no congruent sides

straight angle

measures exactly 180°

supplementary angle

two angles whose measures have a sum of 180°