Polygons

Polygon - A polygon consists of three or more coplanar segments; the segments (sides) intersect only at endpoints; each endpoint (vertex) belongs to exactly two segments; no two segments with a common endpoint are collinear.

Polygons are named by writing their consecutive vertices in order.

Polygons

A polygon is classified by its number of sides:

3 - triangle 7 - heptagon

4 - quadrilateral 8 - octagon

5 - pentagon 9 - nonagon

6 - hexagon 10 - decagon

Polygons

Convex – A polygon such that when the sides are extended, none of them pass through the interior of the polygon.

Concave - A polygon such that when the sides are extended, at least one of them passes through the interior of the polygon.

Polygons

Perimeter - The perimeter of a polygon is the sum of the lengths of its sides.

Area – The space contained within the boundaries of the polygon.

Regular Polygon – A convex polygon in which all sides are congruent and all angles are congruent.

Answer: triangle, convex, regular

Answer: quadrilateral, convex, irregular

Name each polygon by the number of sides. Then classify it as convex or concave, regular or irregular.

a.

b.

SEWING Miranda is making a very unusual quilt. It is in the shape of a hexagon as shown below. She wants to trim the edge with a special blanket binding. The binding is sold by the yard.

a. Find the perimeter of the quilt in inches. Then determine how many yards of binding Miranda will need for the quilt.

Answer: 336 in., yd

Find the perimeter of quadrilateral WXYZ with W(2, 4), X(–3, 3), Y(–1, 0), and Z(3, –1).

Answer: about 17.9 units

The length of a rectangle is 7 more than five times its width. The perimeter is 134 feet. Find the length of each side.

Answer: