# At a Glance - 3D Objects (Prisms, Cylinders, Cones, Spheres)

Three‐dimensional objects are the solid shapes you see every day, like boxes, balls, coffee cups, and cans.

Here are some helpful vocabulary terms for solids:

• Face: a flat side of a 3‐dimensional object.
• Base: one of two parallel, congruent sides of an object.
• Edge: the intersection of two faces on a solid object. This is a line.
• Prism: a solid object with two congruent and parallel faces.
• Pyramid: a solid object with a polygon for a base and triangles for sides.

## Say Hello to the 3-D Shapes

 Name Properties Picture Rectangular Prism A prism with rectangular bases.There are six faces.All faces meet at 90 degrees.Opposite faces are parallel. Cube A prism with six congruent faces.All faces meet at 90 degree angles.Opposite faces are parallel.It is a form of rectangular prism. Triangular Prism A prism with triangular bases.Only the bases are parallel. Octagonal Prism A prism with octagons for bases.Opposite faces are parallel. Triangular Pyramid, aka Tetrahedron A pyramid with a triangular base.A tetrahedron made up of four equilateral triangles is called a regular tetrahedron. Square Pyramid A pyramid with a square base. Cylinder A solid with two parallel circular bases.If you "unwrap" the middle section and lay it flat, it is a rectangle. Cone A solid with a circular base and a curved side that ends in one pointIt has one vertex. Sphere A solid figure where all points are an equal distance from the center point.It's a ball.

#### Exercise 1

Fill in the blank with always, sometimes, or never. A prism ____________ has parallel bases.

#### Exercise 2

Fill in the blank with always, sometimes, or never.  A tetrahedron ___________ has 4 equilateral triangles.

#### Exercise 3

Fill in the blank with always, sometimes, or never.  A prism ___________ has 6 faces.

#### Exercise 4

Fill in the blank with always, sometimes, or never.  Two faces on a cone are ___________ parallel.

#### Exercise 5

Fill in the blank with always, sometimes, or never.  In a prism, opposite faces are _________ parallel.