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mixed number

A mixed number is the sum of a whole number and a fraction.


when two lines cross

point of intersection

the place where the lines cross

parallel lines

if two lines in the same plane do not intersect


if two lines make square corners

right angles

angles made by perpendicular lines

straight angle

two right angles

acute angle

an angle smaller than a right angle

obtuse angle

an angle smaller than a right angle


the number of sides is always equal to the number of vertices


each segment of a polygon

vertex {plural: vertices}

endpoint of a side

concave polygon

if a polygon has a indentation

convex polygon

any polygon that does not have an indentation


quadrilateral that has two pairs of parallel sides


is a quadrilateral that has exactly two parallel sides


equilateral parallelogram


rhombus with four right angles


measure around or distance around


distance from the center of the circle


twice the length of the radius


perimeter of a circle

circumference of a circle

pi D=pi(2r)=2(pi)r

infinte numbers

(1, 3, 5, 7 ....)

finite numbers

(1, 3, 4, 6 )

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