Chapter 12.1 and 12.2

Chapter 12.1 and 12.2

Let’s start with some review!

What is a hexagon and what is an octagon?

Those are what we call 2 dimensional shapes.

– We have learned the names of these shapes and found their areas

In chapter 12, we are going to work with 3 dimensional shapes or solids.

Solid- is a three dimensional figure that encloses a part of space.

1. Prism- is a solid formed by polygons. Prisms have two congruent bases that lie in parallel planes.

This would be called a triangular prism.

This would be called a heptagonal prism.

2. Pyramid: is a solid formed by polygons. The base can be ANY POLYGON, and the other polygons are triangles.

Vertex

edge

Face

3. Cylinder: is a solid with two congruent circular bases that lie in parallel planes.

4. Cone: is a solid with one circular base.

5. Sphere: is a solid formed by all points in space that are the same distance from a fixed point called the center.

Using your notes, let’s do some practice together.

Relay Stations!Find one partner to work with and share a loose leaf paper and writing utensil between the two of you.

Around the room you will find 3-D shapes or objects that you must classify in order to move on!

You will need to match the shape name with the number(s) found at each station.

In order to move on to your homework, I need 8 groups with all the correct answers!!

Now it’s your turn to practice on your

own!Compete the following problems in your text book:

Green: Page 634-635 (20-30all)Yellow: Page 633-634 (12-22all)

Red: Page633 (1-13all)

12.2 Sketching solids and their Nets

How to sketch a prismStep 1 draw 2 congruent rectangles

Step 2 connect corresponding vertices using line segments

Step 3 change any “hidden lines” to dashed lines

Practice this in your notes along with me!

How to sketch a pyramid

Step 1 sketch a pentagon for the base and draw a dot directly above the pentagon

Step 2 connect the vertices of the pentagon to the dot.

Final step is to change any “hidden” lines to dashed lines.

Views of a solid

• Top view

• Side view

• Front view

Draw the top view of a cylinder

Draw a side view of a cylinder

Draw the frontal view of a cylinder

Drawing nets

• Nets are a two-dimensional representation of a solid.

**think of this as un-folding a solid.

Net of a cube:

Net of a rectangular prism

PRACTICE!

• For your practice you need to First: sketch each solid belowThen: draw their top, front, side view and their

net.– cone– Rectangular pyramid

Take your time!

HOMEWORK

• Green: page 638-639 (15-24all)• Yellow: page 638-639 (11-20all)• Red: page 638 (1-12all)