2 PolygonA 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.
8 Name these polygons: A E B C F D A. triangle B. Quadrilateral C. PentagonD. HexagonE. OctagonF. DodecagonEBCFD
9 Polygons with all sides and angles equal are regular polygons Polygons with all sides and angles equal are regular polygons. Circle the regular polygons:
10 Polygons are named by naming consecutive vertices in order. Circle all the correct names for this polygon:pentagon ABCDEpentagon AEDCBpentagon ACDBEpentagon DCBAEpentagon BDCAEpentagon BAEDC
11 What 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.
12 Now, 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 ↑
17 What 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°
18 What is the sum of the angles in this hexagon? 720°
19 What is the sum of the angles in this pentagon? 3 x 180° =540°
20 Do 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!
21 What 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°
22 Find the missing angle measure in this polygon: 180(5-2)= 180(3)= 540°540° = X540 = X116° = X
23 Find the missing angle measure in this polygon: 180(9-2)= 180(7)= 1260°1260° = X1260 = X121° = X
24 raise your achievement practice willraise your achievementThe End