triangle – a three-sided polygon
perimeter – the distance around the outside of a closed two-dimensional shape
parallel – two lines that are always the same distance apart and will never meet
volume – the amount of space occupied by a three-dimensional object
equilateral – a polygon with all sides equal in length
radius – a line segment from the center of a circle or sphere to any point on its circumference
acute angle – an angle that measures less than 90 degrees
right triangle – a triangle with one angle measuring 90 degrees
complementary angles – two angles that add up to 90 degrees when combined
slope – the steepness of a line on a graph or in a coordinate system