34 terms

acute angle

An angle that measures less than 90 degrees.

acute triangle

A triangle in which all three angle are less than 90 degrees.

angle

Two rays that share a common endpoint.

supplementary angles

adjacent angles that equal 180 degrees

complimentary angles

Adjacent angles that equal 90 degrees.

area

The number of square units inside a closed figure.

circle

A closed round shape with a measure of 360 degrees.

intersecting lines

Lines that cross each other at a point.

line

A straight path that goes on forever in both directions.

obtuse angle

An angle that is bigger than a right angle.

obtuse triangle

A triangle with one obtuse angle.

parallel lines

Lines that will never cross, even if they are extended forever.

perimeter

The distance around the outside edge of a closed figure.

perpendicular lines

Lines that form right angles where they cross.

polygon

A closed figure made up of line segments.

quadrilateral

A polygon with 4 sides and 4 angles.

pentagon

A polygon with 5 sides and 5 angles.

hexagon

A polygon with 6 sides and 6 angles.

octagon

A polygon with 8 sides and 8 angles.

rectangle

A quadrilateral with 4 right angles.

square

A quadrilateral with 4 right angles and 4 equal sides.

trapezoid

A quadrilateral with one pair of parallel sides.

parallelogram

A quadrilateral with two pairs of opposite parallel sides.

rhombus

A quadrilateral with two pairs of parallel sides, and all 4 sides of equal length.

ray

A straight path with one endpoint, that goes on forever in the other direction.

right angle

An angle with a measurement of exactly 90 degrees.

line segment

A straight path between two endpoints.

line of symmetry

A line that cuts a figure into two parts that are the mirror image of each other.

straight angle

An angle that measures exactly 180 degrees.

equilateral triangle

A triangle with 3 equal sides and 3 acute angles that are also equal.

isosceles triangle

A triangle with 2 equal sides.

scalene triangle

A triangle with no equal sides.

right triangle

A triangle with one right angle.

triangle

A polygon with 3 sides and 3 angles