1.) part of a line with one endpoint and extends without end in one direction 



2.) two angles whose sum is 90 degrees 



3.) two angles whose sum is 180 degrees 



4.) a polygon with 3 sides 



5.) two rays with a common endpoint 



6.) a triangle with exactly one right angle 



8.) a triangle with one obtuse angle 



10.) a triangle with two congruent sides 



11.) a triangle with no congruent sides 



12.) a closed figure made up of 3 or more line segments. 



13.) a polygon with four sides 



14.) a quadrilateral with both pairs of opposite sides parallel 



7.) a triangle with 3 acute angles 



15.) a quadrilateral with exactly one pair of parallel sides 



16.) a parallelogram with four congruent sides 



17.) a rectangle with four congruent sides 



18.) a parallelogram with four right angles 



19.) a trapezoid with two congruent nonparallel sides 



20.) a trapezoid with two right angles 



9.) a triangle with three congruent sides 


