Polygons A closed plane figure whose sides are

Polygons: A closed plane figure whose sides are segments that intersect only at their endpoints. Regular Polygon: REGULAR TRIANGLE All sides have the same length and angles have the same measure. REGULAR QUADRILATERAL Convex: A polygon is convex if a segment joining any two interior points lies completely within the polygon REGULAR PENTAGON Concave: A polygon that is not convex REGULAR HEXAGON

Polygons # of Sides Directions: 1. Tell whether the figure is a polygon. If it is a polygon, classify it and tell whether it is convex or concave. If not, explain why. 2. 3.

Quadrilaterals: A polygon with four sides Some quadrilaterals have special names based on whether they have parallel or congruent sides and whether they have right angles. Name: Sides: Angles: TRAPEZOID PARALLELOGRAM RHOMBUS Exactly one pair of parallel sides Both pair of opposite sides are parallel Four congruent sides RECTANGLE SQUARE Four congruent sides Four right angles

Diagonal of a polygon: A segment that joins two vertices that are not adjacent To find the sum of the interior angles of a polygon, you can TRIANGLES using _______. DIAGONALS cut up the polygon into ______ The sum of the interior angles of a triangle is: Multiply by the number of triangles Divide by the number of angles to find each angle measure 1. Find the measures of the interior angles on each of the regular polygons. 2. Find the value of x.