Lesson 1 6 Polygons Lesson 3 4 Polygons

Lesson 1 -6 Polygons Lesson 3 -4: Polygons 1

Polygons Definition: A closed figure formed by a finite number of coplanar segments so that each segment intersects exactly two others, but only at their endpoints. These figures are Lesson 3 -4: Polygons 2

Classifications of a Polygon : No line containing a side of the polygon contains a point in its interior : A polygon for which there is a line containing a side of the polygon and a point in the interior of the polygon. Lesson 3 -4: Polygons 3

Classifications of a Polygon : : A convex polygon in which all interior angles have the same measure and all sides are the same length Two sides (or two interior angles) are not congruent. Lesson 3 -4: Polygons 4

Polygon Names 3 sides Triangle 4 sides Quadrilateral 5 sides Pentagon 6 sides Hexagon 7 sides Heptagon 8 sides Octagon 9 sides Nonagon 10 sides Decagon 12 sides n sides Dodecagon n-gon Lesson 3 -4: Polygons 5

Perimeter of a Polygon The perimeter of a polygon is the sum of the lengths of its sides, which are segments. s l a b s w w l s s c Rectangle Triangle P=w +l+w+l P=a+b+c P = 2 w + 2 l Square P=s+s+s+s P = 4 s Reminder: distance formula Lesson 3 -4: Polygons 6

Name each polygon by its number of sides. Then classify it as convex or concave and regular or irregular. 1. 2. Lesson 3 -4: Polygons 7

A landscape designer is putting black plastic edging around a rectangular flower garden that has length 6. 4 meters and width 5. 7 meters. The edging is sold in 5 -meter lengths. A) Find the perimeter of the garden and determine how much edging the designer should buy. B) Suppose the length and width of the garden are tripled. What is the effect on the perimeter and how much edging should the designer buy? Lesson 3 -4: Polygons 8

Find the perimeter of triangle ABC if A(4, 4), B(-4, 2) and C(3, -3). Lesson 3 -4: Polygons 9

Use Perimeter to Find Sides l The length of a rectangle is five times the width. The perimeter is 4 yards. Find the length of each side. Lesson 3 -4: Polygons 10

Find the length of each side of the regular polygon for the given perimeter. P = 120 meters P = 156 feet Lesson 3 -4: Polygons P = 81 inches 11