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Two-Dimensional Figures. Notes 4 – Section 1.6. Essential Learnings. Students will understand and be able to identify and classify polygons. Vocabulary. Polygon – a closed figure formed by a finite number (more than 2) of straight segments called sides.
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Two-Dimensional Figures Notes 4 – Section 1.6
Essential Learnings • Students will understand and be able to identify and classify polygons.
Vocabulary • Polygon – a closed figure formed by a finite number (more than 2) of straight segments called sides. • Vertex of a polygon – the vertex of each angle in a polygon.
Vocabulary • Convex polygon: • Concave polygon: No points of the lines are in the interior. Some of the lines pass through the interior.
Classifying Polygons • Polygons are classified by its number of sides. Number of SidesPolygon 3 Triangle 4 Quadrilateral 5 Pentagon 6 Hexagon 7 Heptagon
Classifying Polygons • Polygons are classified by its number of sides. Number of SidesPolygon 8 Octagon 9 Nonagon 10 Decagon 12 Dodecagon n n-gon
More Vocabulary • Equilateral polygon – a polygon in which all sides are congruent. • Equiangular polygon – a polygon in which all angles are congruent. • Regular polygon – a convex polygon that is both equilateral and equiangular. An irregular polygon is a polygon that is not regular.
Example 1 • Name each polygon by its number of sides. Then classify it as convex or concave and regular or irregular. Pentagon Convex Regular
Example 2 • Name each polygon by its number of sides. Then classify it as convex or concave and regular or irregular. Heptagon Concave Irregular
Example 3 • Name each polygon by its number of sides. Then classify it as convex or concave and regular or irregular. Quadrilateral Convex Irregular
Notation in Diagrams PropertySymbol Parallel // Perpendicular Equilateral all sides are congruent Equiangular all angles are congruent
Triangles • Three types of triangles: Scalene – three sides of different lengths Isosceles – two sides that are equal in length, the third side is the base Equilateral – all three sides are the same length
Triangles Identifying triangles by the largest angle: Acute – between 0 and 90 Right – 90 angle Obtuse – between 90 and 180 A = ½ bh P = sum of sides
Quadrilaterals • Quadrilaterals are 4-sided figures. • There are 6 special quadrilaterals to know: Paralellogram Rhombus Rectangle Square Trapezoid Kite
Parallelogram • Opposite sides are parallel and congruent • Opposite angles are congruent A = bh P = sum of sides
Rhombus • All sides are congruent, opposite sides are parallel • Opposite angles are congruent • Diagonals bisect at a right angle A = ½ d1d2 P = sum of sides
Rectangle • Opposite sides are parallel and congruent • Four right angles A = bh P = sum of sides
Square • All sides are congruent, opposite sides are parallel • Four right angles A = bh P = sum of sides
Trapezoid • One pair of opposite sides are parallel • Isosceles trapezoid has two sides congruent A = ½ (b1+b2)h P = sum of sides
Kite • Two pairs of consecutive congruent sides • One pair of opposite angles are congruent • Diagonals bisect at a right angle • The longer diagonal bisects the smaller diagonal A = ½ d1d2 P = sum of sides
Assignment Page 61: 11-25, 34-36 Sketch & Label Diagrams WS Math’s Mates 1-1