 Chapter 24 Polygons.

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Chapter 24 Polygons

Learning Outcomes Find missing interior angles in a polygon
Find missing exterior angles in a polygon Find missing interior angles in a regular polygon Find missing exterior angles in a regular polygon Tessellate shapes

Polygons All shapes with straight sides 3-sided Triangle
4-sided Quadrilateral 5-sided Pentagon 6-sided Hexagon 7-sided Heptagon 8-sided Octagon 9-sided Nonagon 10-sided Decagon

Interior Angles Remember a triangle adds to 180o!

Sum of Interior Angles Sum of Interior Angles = Number of
Triangles × 180 Sum of Interior Angles = (n – 2)× where n = number of sides

Exterior Angles Remember a straight line adds to 180o!

Sum of Exterior Angles Sum of ALL exterior angles = 360o

Regular Polygons Regular polygon has equal sides and equal angles
1 exterior angle = 360 ÷ number of sides 1 interior angle = 180 – exterior angle

Examples Find the exterior and interior angle in a regular heptagon
Calculate the number of sides in a polygon if its exterior angle is 24o Calculate the number of sides in a polygon if its interior angle is 171o

Tessellations Tessellating means tiling