What is a Triangle?

Nico and Nia are having lunch at their favorite restaurant,(...)Three Corners Cafe. “I sure am hungry, Nia!” “MEEEE TOOOO!” “Everything looks delicious!” “How are we going to choose what to eat?” " We can order the Three Corners Special." "What is the Three Corners Special?" " It is any food on the menu that is a triangle shape!" : "But how will we know which food is a triangle?" We can help Nico and Nia order their lunch by finding foods that are in the shape of Triangles A triangle is a shape. Shapes are two-dimensional figures that we can name based on their "defining attributes". Defining attributes are characteristics that a shape MUST HAVE. Let's look at a triangle. The defining attributes of a triangle are that it must be a closed shape that has… three sides… three corners… and three angles… Shapes also have NON-defining attributes. If defining attributes are characteristics a shape MUST have, what are non-defining attributes? A NON-defining attribute is something that a shape has, but doesn’t always have to be the same. SIZE is an example of a non-defining attribute. A triangle can be big(...), big,(...) BIG… or a triangle can be small,(...)small,(...)_ small. Color is another non-defining attribute. Triangles can be ANY color! Triangles can also face many different directions. Let's identify some triangles! Is this a triangle? Start by counting the sides… It has one,(...) two, (...) three sides. Now count the corners. It has one,(...), two,(...) three corners. Finally, count the angles on the inside. It has one, (...) two,(...) three angles on the inside. Yes, this shape is a triangle! How about this shape? Is this shape a triangle? Start by counting the sides. One,(...) two, (...), three, (...) FOUR. Wait a minute (...) this shape has FOUR sides! Since we know that triangles MUST have three sides, we know that this is NOT a triangle! Let’s try ONE more! Count the sides… Count the corners... Count the angles. Yes, this is a triangle because it has all the defining attributes of a triangle. Now that we know all the attributes of a triangle, let’s help Nico and Nia find which foods to order for lunch. Look at the menu! Can you point to all of the foods that have a triangle shape? Here’s one! (...) This slice of pizza! This slice of pizza has all the attributes of a triangle! Here is another one! A triangle is made by this half of a sandwich! There is one on this slice of cake! And the last one is found from this slice of watermelon! Remember, (...) Shapes have defining and non-defining attributes A triangle is a closed shape that always has three sides, three corners, and three angles. But, a triangle can be any size(...) or color(...) and face any direction. "Yum! This lunch is delicious!" "Yes! It's TRI-iffic!"