Does anyone want to classify my figure? Classify ing TwoDimensional Figur Mikes Math Mall Made Easy es Classifying 2-Dimensional Figures In life, we like to group objects in categories based on their properties. Placing objects into categories makes it easier to compare them with other objects. I struggle with this junk all the time!

Really? How so? Im always wonderingcan a soft taco be grouped with a burrito? Or is a quesadilla just a smashed burrito sandwich? I feel your pain? Classifying 2-Dimensional Figures Lets look at some vocabulary terms before we start classifying figures. Two-dimensional having a width and a height but flat like a piece of paper. Polygon Two-dimensions Polygon a two-dimensional shape made up

of straight lines that are closed. Three-dimensions One-dimension Classifying 2-Dimensional Figures Here is a list of the most basic polygons: Triangle 3-sided Hexagon 6-sided Quadrilateral 4-sided Pentagon 5-sided Heptagon 7-sided Octagon

8-sided Classifying 2-Dimensional Figuresare either regular or irregular. Polygons This is a regular pentagon because ALL of its sides and angles are congruent. Congruent having the same measure Hash marks indicate sides with the same length. Angle arcs indicate angles of the same measure. This is an irregular pentagon because some of its sides and angles are not congruent. Part I i y f i s s a l C ng

a i r T e l g n Yep! I got it on sale! Properties of Triangles All triangles have: 3 sides 3 interior angles (that add up to 180) Yeah, but arent there like a bazillion different kinds of triangles?

I wouldnt say a bazillion! Just a few? One must know what one is getting into before one gets into it, Professor! Why, are we counting? There are just a few basic ways that we classify or name triangles! Just check this out! Classifying Triangles We classify or name triangles by their angles. Acute Triangle All angles < 90

All angles less than 90 Right Triangle One 90 angle means 90 One 90 angle Obtuse Triangle One angle greater than 90 One angle > 90 Classifying Triangles We also classify triangles by their side lengths and angle measures. Equilateral Triangle 3 congruent sides All angles congruent Isosceles Triangle 2 congruent sides

2 congruent angles Scalene Triangle No congruent sides No congruent angles Name that Triangle! Classify each triangle by ALL names that apply. 2. ____________________ Acute 1. ____________________ Isosceles 3. ____________________ Right ____________________ Isosceles

140 Obtuse ____________________ Scalene ____________________ Classifying Triangles So, what do think about classifying triangles, Mr. Sparkles? This doesnt seem too rough, but Ive never seen a cute triangle? Thats not what acute actually means! Its nothing personal. I simply find triangles fairly unattractive. Are they cute?

Im not paid enough! Maybe we should just go take a look at some quadrilaterals now! Part II i y f i s s a l C ng a u Q ls a l i

r d r te I know what youre thinking sweet lid, right? Properties of Quadrilaterals Another main group of polygons are the quadrilaterals. All quadrilaterals have: 4 sides 4 interior angles (that add up to 360) How can I classify these things when I dont even know what a cordlaratamal is? Have you ever heard of a square? Yeah, duh!

Just checking to see if youre awake! Well, squares are quad-ri-lat-er-als! Classifying Quadrilaterals Lets classify quadrilaterals from those with the fewest properties to those with the most properties. Basic Quadrilateral 4-sided polygon Trapezoid Quadrilateral with one pair of parallel sides Parallel Lines Two lines on the same plane that will never cross. They are always the same distance apart. Classifying

Quadrilaterals Parallelogram Rectangle Two pairs of parallel sides Opposite sides congruent A parallelogram Four 90 angles By definition, rectangles are considered parallelograms. Why cant parallelograms be classified as rectangles? Parallelograms do not have 4 congruent angles. Classifying Quadrilaterals Square Rhombus A parallelogram 4 congruent sides

A parallelogram A rectangle A rhombus Why can we classify a square as a rectangle and a rhombus? A square is a parallelogram with 4 right angles (rectangle) A square is a parallelogram with 4 congruent sides (rhombus) WORD BANK equilateral triangle pentagon rectangle parallelogram right triangle octagon trapezoid square rhombus 5.

1. YIELD trapezoid Higher Coff Grounds ee 3. parallelogram F FA Future Farmers of America righ t tr World Cup iang 2014 eq uil tria ater ngl al

e Classifying 2-Dimensional Figures Name each of the following polygons. 2. ITALIA 6. le 4. Work Zone trapezoid Trail 3 pentagon Classifying 2-Dimensional Figures Answer the following questions. 1. What do the hash marks indicate on the sides of polygons?

Hash marks indicate that those side lengths are congruent. 2. Whats the difference between a regular and irregular polygon? A regular polygon has sides and angles that are all congruent. An irregular polygon does not. 3. By definition, we can classify all rectangles as parallelograms, but why cant we classify parallelograms as rectangles? A rectangle has two pairs of parallel sides and two pairs of congruent sides as defined by a parallelogram. However, a rectangle has four 90 right angles which is not included in the definition of a parallelogram. 4. Whats the difference between an obtuse angle and an acute angle? An obtuse angle is greater than 90, and an acute angle is less than 90. Classifying 2-Dimensional Figures Match each term with one of the figures. 1. Scalene Obtuse Triangle _____ H 4. Trapezoid _____ A 2. Rhombus _____ G

5. Isosceles Triangle _____ B 6. Equilateral Triangle_____ I 8. Parallelogram _____ C 7. Octagon _____ E 9. Irregular Quadrilateral _____ D I A E 3. Regular Pentagon _____ F F B

G C D 120 H Classifying Quadrilaterals So how do you feel about classifying two-dimensional figures, Sparky? I am a classifying polygaterals and quadrigonials beast,Its sir!a promise, sir! Im not sure you Ok! How many sides does a heptagon have?

Ill prove it! Ask me a question! Thats easy! Extinct dinosaurs dont have any sides! Promise me youll look over the notes! Mikes Math Mall