Three-dimensional figures can be made up of flat or curved surfaces. Prisms and pyramids are named by the shapes of their bases.
A flat surface is called a face. An edge is the intersection of two faces. A vertex is the intersection of three or more faces.
A net is a diagram of the surfaces of a three-dimensional figure that can be folded to form the three-dimensional figure.
The net at the right has one rectangular face. The remaining faces are triangles. The net forms a rectangular pyramid.
A cross-section is the intersection of a three-dimensional figure and a plane.
Since the figure on the left is a rectangular pyramid, the cross section is a rectangle.
An isometric drawing is drawn on isometric dot paper and shows three sides of a figure from a corner view. A solid and an isometric drawing of the solid are shown in the image on the right.
Orthographic views show three-dimensional objects from six different perspectives.
Top: Picture yourself above the figure and looking straight down.
Front: Choose one side of the figure to be the front. Visualize looking straight at the figure.
Right: Picture walking around to the right side of the figure and looking straight at it.
Bottom: Picture yourself directly underneath the figure and looking straight up.
Left: Picture walking around the corner to the left side of the figure and looking straight at it.
Back: Picture walking around to the back of the figure and looking straight at it.
A perspective drawing shows parallel lines drawn such that they meet at a vanishing point. In a one-point perspective drawing, nonvertical lines are drawn so that they meet at a vanishing point.
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