Ask "What is a triangle?". 2. Using Sketchpad, create a variety of shapes (examples and non-examples of triangles). Begin with open and closed shapes, and shapes with or without straight sides.

The orientation of the triangle means that the base is not necessarily horizontal or the lowest side of the shape. Image caption, For triangles that are not right-angled, the base is one of the ...

Image caption, The longest side of a triangle is opposite the ... You may need a pen and paper to help you with your answers. A triangle is a rigid shape and is used in the construction of bridges.

Rectangles, arches, and triangles are the most common shapes used to build big structures. What happens when you push the side of a rectangle? The rectangle is a wobbly, unstable shape.