2PolygonA closed figure formed by joining three or more segments in a plane at their endpoints, with each line segment joining exactly 2 others.Each line segment is called a side of the polygon.This polygon has 8 sides.
8Name these polygons: A E B C F D A. triangle B. Quadrilateral C. PentagonD. HexagonE. OctagonF. DodecagonEBCFD
9Polygons with all sides and angles equal are regular polygons Polygons with all sides and angles equal are regular polygons. Circle the regular polygons:
10Polygons are named by naming consecutive vertices in order. Circle all the correct names for this polygon:pentagon ABCDEpentagon AEDCBpentagon ACDBEpentagon DCBAEpentagon BDCAEpentagon BAEDC
11What is the sum of the angle measures in a triangle? Please draw a triangle on a piece of scratch paper. It can be any size or shape, just be sure it is a triangle.
12Now, tear off the three angles of the triangle Now, tear off the three angles of the triangle. Position the angles side-by-side on your desk. What shape do they make?a straight line!Draw the angles side-by-side on your paper like this ↑
17What is the sum of the angle measures in a polygon? We can divide the polygon into triangles, then multiply the number of triangles by 180°How many triangles make up this quadrilateral?2What is the sum of the angles of this quadrilateral?2 x 180° = 360°
18What is the sum of the angles in this hexagon? 720°
19What is the sum of the angles in this pentagon? 3 x 180° =540°
20Do you HAVE to draw the triangles to find out how many of them there are in a polygon? NO!4 sides, 5 sides, sides,2 triangles triangles trianglesn sides,n-2 triangles!
21What is the sum of the measures of the angles of these polygons? 180(6-2) 180(8-2) 180(10-2)= 180(4) =180(6) = 180(8)= 720° = 1080° =1440°
22Find the missing angle measure in this polygon: 180(5-2)= 180(3)= 540°540° = X540 = X116° = X
23Find the missing angle measure in this polygon: 180(9-2)= 180(7)= 1260°1260° = X1260 = X121° = X
24raise your achievement practice willraise your achievementThe End