Quadrilateral – any four sided polygon Parallelogram – a quadrilateral whose opposite sides are parallel and congruent Rectangle – a parallelogram with four right angles Square – a parallelogram that has 4 right angles and 4 congruent sides Trapezoid – a quadrilateral with exactly one pair of parallel sides. Rhombus – a parallelogram with all sides the same length. Radius- a line segment with endpoints at the center of the circle and on the circle.(radii is the plural of radius) Diameter – a line segment that passes through the center of a circle and has both endpoints on the circle Chord – any line segment with both endpoints on a circle. A diameter is a special chord You can classify a triangle by their angles and their sides.
Right triangle – a triangle that has one right angle Obtuse triangle – has one obtuse angle Acute triangle – has three acute angles Scalene triangle – a triangle with no sides that are equal in length Isosceles triangle – a triangle with at least two sides that are equal in length Equilateral triangle – a triangle whose three sides are congruent.