Module 9: Draw and Analyze 2D Figures

I CAN Draw and Construct circles and Triangles.

7.EE.B.4a

7.G.A.2
7.G.B.5

The Fire Pit.

Parker plans to build a circular fire pit in a square area. He is drawing a model on paper to confirm his plans before he starts to build. How can Parker use paper folding and a compass to draw the largest possible circular fire pit in the space he has staked off?

A COMPASS is used to draw circles on blueprints as a SCALE DRAWING to represent the actual object.

Which one of these tools on the left is a compass?

So parker needs to draw a circle to represent his fire pit.

Multiple Choice

Which tool is a compass?

​The distance from the center point to the outside edge of a circle.

​​Radius

The distance from 1 side of the circle to the other in a line that goes through the center point of the circle.

​​Diameter

​What is the diameter of a circle in relation to its radius?

Equation

Multiple Choice

What equation shows the diameter in relation to the radius of a circle:

• d = 2r

• r = d/2

• d = r*3

• d = r^2

Multiple Choice

What equation shows the radius in relation to the diameter of a circle?

• d = 2r

• r = d/2

• d = r*3

• d = r^2

How can Parker use paper folding and a compass to draw the largest possible circular fire pit in the space he has staked off?

​THINK! : How can I fold this piece of paper so that I can use my compass to draw the largest circle possible on this piece of paper?

4 MINUTES!

If you finish early, label the RADIUS and DIAMETER.

Activity: Drawing the largest circle possible on a piece of paper.

This will be the exact center point of the page. Place the point of the compass there.

Find where the lines cross in the middle of the page.

Fold the paper hot dog style, then unfold. Fold paper hamburger style, then unfold.

Fold the paper in half.

Twice.

Folding the paper

Then demonstrate how to use the compass to draw the circle.

Place your page with a circle in a folder

You will use it later.

Draw a Triangle with a 50° angle.

In circle 1:

On a new piece of paper draw 3 circles with a 1-inch RADIUS.

If its not possible, tell me why.

A triangle with a side length of 2.5"

In circle 2:

Draw a triangle with a 30° angle and a 60° angle.

In circle 3:

​4 MINUTES!

Match

Match the following

• Circle 1: 50° angle

• Circle 2: 2.5" Side

• Circle 3: 30° and 60° angles

POSSIBLE

NOT POSSIBLE

Possible

• POSSIBLE

• NOT POSSIBLE

• Possible

Put your name on your paper with 3 circles and turn it in.

5 Points for Completion

Up to 5 points for accuracy

10 Points for In-Class Work

EXIT

TICKET

​Be sure that you are writing everything down as you go.

We need to make a scale drawing as a blueprint for this table.

Draw a circle with a 3-inch radius.

Parker has a square piece of wood with a side length of 48 inches. He wants to use it to build the largest circular tabletop that he can to fit over the fire pit.

Fill in the Blank

Parker has a square piece of wood with a side length of 48 inches. He wants to use it to build the largest circular tabletop that he can.

What is the largest diameter of the table he can make?

You must type in your units as well as a number.

Fill in the Blank

Parker has a square piece of wood with a side length of 48 inches. He wants to use it to build the largest circular tabletop that he can.

What is the diameter of the circle you drew on your paper?

You must type in your units as well as a number.

Drag and Drop

So if the scale drawing has a diameter of 6 inches and the real table will have a diameter of 48 inches, how many inches of the table does 1 inch on the scale drawing represent? Meaning the scale is:

drawing : real

​

Placeholder

per ​

Placeholder

Drag these tiles and drop them in the correct blank above

1 inch (drawing)

8 inches (real)

8 inches (drawing)

1 inch (real)

48 inches (real)

48 inches (drawing)

6 inches (real)

6 inches (Drawing)

Turn in your scale drawing of the table with your name on it.

It should have:

1. Your name, date, and period are on it.

2. The scale drawing with a radius of 3 and a diameter of 6 are labeled.

3. The scale factor is written as "scale factor = ____"

4. The Diameter and Radius of the real table are written.