What You Will Accomplish This Unit By the end of this unit you will be able to; Name and create shapes Label Parts of shapes (i.e. Radius of a circle, base of a triangle) Name different triangles. Understand 3-Dimensional objects How you can use polygons to create 3-D objects Name and create 3-dimensional objects Let’s Get Started!!!
Triangles Shapes This diagram shows four main components of a triangle;
Vertex/Vertices: these are the points of the triangle. A triangle will always have three vertices.
Leg or Side: these are the lines that connect the vertices. There are always three sides on a triangle
Angles: these help you determine which type of triangle it is; equilateral, isosceles, or scalene.
Can You Classify Triangles? This is an equilateral triangle. All of its sides are equal. It is also an acute triangle because all its angles are less than 90o This is a right-angle triangle because it has a 90o angle This is an isosceles triangle because two of its sides are the same. This is an obtuse triangle because one of its angles is larger than 90o
Squares Rectangles Shapes Con’t I have 2 sets of equal sides All my sides are equal It is important to recognize the differences between squares and rectangles.
Circles Shapes Con’t This diagram shows four major components of a circle;
Centre: this is the centre of the circle, and the distance from this point to any point on the circumference is the same.
Radius: this is the distance from the centre point to any point on the circumference.
Diameter: this is the entire distance from one side of the circle to the other. The diameter is twice the distance of the radius.
Circumference: this is the distance around the entire circle.
A polygon is; A plane shape (two-dimensional) with straight sides that must connect.In a simple polygon none of the sides overlap. In a complex polygon the sides overlap.(Note: a circle is not a polygon because it has a curved side) Polygons
Can you name and recognize different polygons? Naming and Recognizing Polygons Am I a simple or complex polygon? What’s my name? What’s my name, and what kind of polygon am I?
To name a polygon you must be able to count the number of sides it has.
Are these the only polygons? No!Polygons can have an infinite number of sides. Can you name them all? Naming Polygons I have 6 sides, therefore, I must be a hexagon! I have 10 sides, therefore, I must be a decagon! BONUS* The shapes above are known as simple polygons. Do you remember what a complex polygon looks like?
We are complex polygons! Did you remember how we looked? How do you know these are complex polygons? The easiest way to know if a polygon is complex is to ask yourself one simple question; Do any of the lines cross?
Yes. Then this polygon is a complex polygon.
No. Then this is not a complex polygon. It would be known as a simple polygon.
I’m not sure how to recognize what is and what is not a polygon. If you are not sure if it is a polygon there are simple questions you can ask yourself to identify them. Is This A Polygon? Q&A.
Q&A Con’t Is it on a plane? Or is it 2-Dimensional? In other words if you laid it in front of you would it lay flat? If the answer is yes then you can move on to the next question! YES NO
2. Do all the sides connect? In other words are there no holes within the shape? If the answer is yes then you can move on to the next question! Q&A Con’t NO YES
Does it have three or more sides? If you answer yes again then this shape is a polygon! That’s all! 3 Simple questions and now you can identify a polygon! Q&A Con’t NO YES NO
Now you ask, what does that even mean?? 3-Dimensional Objects
So a 3-Dimensional object exists in three dimensions. Well that definition is not very helpful. What is three dimensions? Well a 3-Dimensional object has depth. Refer back to polygons. These objects had a width and a length. 3-D objects will have width, length ANDdepth. Use a box as an example! *See how this box has a length, width and depth. * A 3-D object will never lie flat. If you place it on a desk it will stand out from the desk.
Now that we know what 3-D objects are let’s try to name them! 3-Dimensional Objects Name (*Note: these are only some 3-D bjects) Sphere Cube Rectangular Prism Cone Definitions
Has a circle base that extends up to a point. Ex. Ice Crem Cone
Can You Match The 3-D Objects To Their Name? Sphere Cone Cube Rectangular Prism
What are Prisms? A prism is a polyhedron with two congruent and parallel faces. Basically if you take two of the same polygons and connect them so that they are parallel you will get a prism. Here is an example,
Types of Prisms Try to use your knowledge of polygons to identify these prisms... Do you recognize this prism? It’s a cylinder! This is a pentagonal prism This is a triangular prism *BONUS: add ‘al’ to the end of polygon names plus ‘prism’ at the end to name the types of prisms. There are two exceptions and they are rectangular and triangular prisms.
Geometry Activities Con’t 3-Dimensional Objects Have students cut out this model and fold it into a cube! There are outlines like these all over the internet! Let your students explore which 3-D shapes they can make. http://www.korthalsaltes.com/
Here’s Some Extra Bonus Help! Get these books to help add to your geometry unit!! Use this slideshow to aid your students with geometry shapes, polygons and 3-Dimensional objects, or for your own teaching reference!