6.14 Polygons The student will identify, classify, and describe the characteristics of plane figures, describing their similarities, differences, and defining properties.

6.14 Vocabularypage 70 TRIANGLES- Three sides polygons Congruent- same size and shape NAMING TRIANGLES BY THEIR SIDES Equilateral triangle –A triangle in which all three sides and all three angles are congruent. Isosceles triangle –An isosceles triangle has two congruent sides and two congruent angles. Scalene triangle –A triangle in which all three sides and all three angles are different (NOT congruent) Page Add the Angles in ALL TRIANGLES and they always add up to 180 degrees!!!! NAMING TRIANGLES BY THEIR ANGLES All triangles have at least 2 acute angles. It is the third angle that gives the triangle its name. If the third angle is an acute, then it is an acute triangle. If the third angle is a right angle then it is a right triangle. If the third angle is an obtuse angle, then it is an obtuse triangle.

6.14 Vocabulary continued page 72 (Triangles pg 70) Plane figure – A 2-D figure is also known as a plane figure. Polygon – A simple, closed, 2-D figure formed by three or more sides Parallel – Two or more straight lines, being an equal distance apart everywhere that will not intersect. Quadrilateral –four sides. Parallelogram –A quadrilateral with both pairs of opposite sides congruent and parallel. (rectangle, square, rhombus included) Rhombus –quadrilateral with all sides congruent. Rectangle - A quadrilateral with opposite sides parallel and four right angles. Square –four congruent sides and four right angles Trapezoid – A quadrilateral with one pair of parallel sides. Pentagon –five sides. Hexagon –six sides. Heptagon- seven sides Octagon – eight sides. Nonagon-nine sides Decagon- ten sides Page Triangles- sum of all angles equals 180 degrees Quadrilaterals- Sum of all angles equals 360 degrees For every side added, add another 180 degrees. Pentagon= Hexagon= Heptagon= Octagon = Practice- Name and draw all the parallelograms (there are 4 including the parallelogram itself) Name the triangles by their angles Name the triangles according to their sides