1. 2 1 4 3 6 5 Classify each quadrilateral below with its best name.
rhombus 1
Isosceles Obtuse Triangle 4 3
rectangle
Scalene Right Triangle
trapezoid 6 5
Acute Equilateral Triangle

2. Ch. 7-5 Angles and Polygons

3. Ch. 7-5 Angles and Polygons
Here is a list of Common Polygons:
Polygon Name
Number of Sides
Triangle 3
Quadrilateral 4
Pentagon 5
Hexagon 6
Heptagon 7
Octagon 8
Nonagon 9
Decagon 10
Dodecagon 12

4. -Two consecutive sides of a polygon form one interior angle
-Two consecutive sides of a polygon form one interior angle. The sum of the measures of the interior angles depends on the number of sides.
-For a polygon with n sides, the sum of the measures of the interior angles is (n – 2)1800
Example 1: Find the sum of the measures of the interior angles of each figure below. Remember to use the formula.
a.) nonagon
b.) heptagon
A nonagon has 9 sides so plug in 9 for n
(9 – 2)180 = 7(180) = 1,2600
A heptagon has 7 sides so plug in 7 for n
(7 – 2)180 = 5(180) = 9000

5. Example 2: Find the missing angle measure in the figures below. a.
First find the sum of the measures of the interior angles.
(5 – 2)180 = 5400
1300
920
750
Now add up all of the angle measures that you know and subtract it from 5400 to find out the measure of the missing angle.
= 399
540 – 399 = 1410
1020 x0
b.) A hexagon has 5 angles with measures of 1420, 840, 1230, 900, and What is the measure of the 6th angle?
First find the sum of the measures of the interior angles.
(6 – 2)180 = 7200
Now add up all of the angle measures that you know and subtract it from 7200 to find out the measure of the missing angle.
= 569
= 1510

6. -A regular polygon is a polygon with all sides congruent and all angles congruent.
-To find the measure of each angle of a regular polygon, divide the sum of the angle measures by the number of angles.
Example 3: Find the measure of each angle for the regular polygons below.
a.) a regular octagon b.) a regular decagon
First find the sum of the measure of the interior angles:
(8 – 2)180 = 10800
First find the sum of the measure of the interior angles:
(10 – 2)180 = 14400
Now divide 1080 by 8.
Therefore every angle in a regular octagon is 1350
Now divide 1440 by 10.
Therefore every angle in a regular dodecagon is 1440

7. HW – Pg. 326
Problem #’s 1-5 all, 8-20, even