 # Do Now ChalkUp “Quadrilateral Review”. 3/17/2015 8-3 C Polygons.

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3/17/2015 8-3 C Polygons

polygon- a closed plane figure formed by three or more line segments -named by the # of their sides & angles - regular polygon- a polygon in which ALL sides are congruent and ALL angles are congruent.

Example 1 Tell whether each shape is a polygon. If so, give its name and tell whether it appears to be regular or not regular. The shape is a closed plane figure formed by 3 or more line segments. polygon There are 5 sides and 5 angles. pentagon All 5 sides do not appear to be congruent. not regular

Example 2 Tell whether each shape is a polygon. If so, give its name and tell whether it appears to be regular or not regular. There are 8 sides and 8 angles. octagon The sides and angles appear to be congruent. regular The shape is a closed plane figure formed by 3 or more line segments. polygon

You can divide any quadrilateral into two triangles by drawing a diagonal, a line segment that connects two non-adjacent vertices The sum of the interior angle measures in a triangle = 180° SO…. the sum of the interior angle measures in a quadrilateral = 360°

1. Name each polygon and tell whether it appears to be regular or not regular. 2. What is the measure of each angle in a regular dodecagon (12-sided figure)? 150° nonagon, regular; octagon, not regular Exit Ticket

1. Name the polygon and tell whether it appears to be regular or not regular. A. pentagon, not regular B. hexagon, regular C. heptagon, regular D. octagon, not regular octagon, not regular

2. What is the measure of each angle in a regular decagon (10-sided figure)? A. 108 B. 144 C. 150 D. 140 octagon, not regular

Homework Pg. 476 #1-36 Quiz on Thursday