18.1 Perimeter

Perimeter

Objective: Find the perimeter of geometric shapes

Multiple Choice

Which word describes the distance around a geometric object?

• Area

• Perimeter

• Derivative

• Factor

• Yavin

Perimeter: The distance AROUND a two-dimensional figure.

If the little person was to walk AROUND the rectangle...they would walk 21 ft, then 9 ft, then 21 ft, then 9 ft and be back where they started.

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So 21 ft + 9 ft + 21 ft + 9 ft = 60 ft

Fill in the Blank

What is the perimeter of the figure?

Congruent Sides

If any of the sides are the same length they are called congruent.

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The way it is shown in a picture is a tic mark like: |

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Fill in the Blank

What is the perimeter of the figure?

Fill in the Blank

What is the perimeter of the figure?

Let's Find the Perimeter of this Triangle

• First, write your work out: Side 1 + Side 2 + Side 3

• x + x + 4 + x + 6

• What method can I use to simplify this expression?

Hopefully you said Combine Like Terms

• x + x + 4 + x + 6

• Combine your "x" terms and then Combine your constants

• 3x + 10

• Are we Done?

Multiple Choice

Is the perimeter of this triangle 3x + 10

• yes

• no

Fill in the Blank

Find the perimeter of the shape.

Fill in the Blank

Find the perimeter of the shape.

EXAMPLE

Find the perimeter of the figure.​

Fill in the Blank

What is the perimeter of the figure?

Fill in the Blank

What is the perimeter of the figure?

Parts of a Circle

Multiple Choice

12 inches in this circle represents its

• radius

• diameter

Fill in the Blank

What is the length of the diameter of the circle?

Fill in the Blank

What is the length of the radius of the circle?

Finding Circumference given radius

Finding Circumference given diameter

Multiple Choice

Find the circumference of the circle

• 50.24 yd

• 25.12 yd

• 11.14 yd

Multiple Choice

Find the circumference of the circle

• 18.84 cm

• 75.36 cm

• 37.68 cm

Multiple Choice

Find the circumference of the circle whose radius is 4 in

• 12.56 in

• 25.12 in

• 50.24 in

Multiple Choice

Find the circumference of the circle whose diameter is 10 m

• 31.4 m

• 62.8 m

• 15.7 m