20 terms

trapezoid

a quadrilateral with exactly one pair of parallel sides

isosceles

triangle with two equal sides

octogon

a polygon with eight sides

polygon

a closed plane figure with straight sides

center

the point inside a circle that is the same distance from each point on the circle

diameter

the distance across a circle through its center

compass

a tool used to make circles

equilateral triangle

a triangle with three equal sides and three equal angles

hexagon

a polygon with six sides

pentagon

a polygon with five sides

triangle

a polygon with three sides

square

a parallelogram with four equal sides

parallelogram

a quadrilateral with two pairs of parallel sides

scalene triangle

a triangle with no equal sides

quadrilateral

a polygon with four sides and four angles

radius

a line segment with one endpoint at the center of a circle and the otehr endpoint on the circle

circle

a closed plain figure made up of all the points the same distance from the center

obtuse triangle

a triangle with one obtuse angle

acute triangle

a triangle with three acute angles

right triangle

a triangle with one right angle