9-2 Perimeter and Circumference
Bell Work
What do you think this picture is telling us about area and perimeter?

9-2 Perimeter and Circumference

9-2 Perimeter and Circumference
pi

9-2 Perimeter and Circumference
___________ is the distance around a geometric figure.

9-2 Perimeter and Circumference
Example 1
Find the perimeter.
25 cm 25 cm
15 cm

9-2 Perimeter and Circumference
Example 2
Find the perimeter of the polygon.
25 cm
20 cm
30 cm

9-2 Perimeter and Circumference
Example 3
Find the perimeter of a rectangle.
14 ft
18 ft

9-2 Perimeter and Circumference

9-2 Perimeter and Circumference
Example 4
Find the perimeter of a rectangle.
16 ft
8 ft

9-2 Perimeter and Circumference
Perimeter of a square
6 ft

9-2 Perimeter and Circumference
Example 5
Find the perimeter of a square.
24 ft

9-2 Perimeter and Circumference
The distance around a circle is called _____________.
The formula for circumference is _______________ or ________________.

9-2 Perimeter and Circumference
Example 6
Find the circumference of the circle to the nearest tenth. Use 3.14 for  .
12 in.

9-2 Perimeter and Circumference
Example 7
Find the circumference of the circle to the nearest tenth. Use 3.14 for  .
18 cm

9-2 Perimeter and Circumference
Example 8
The diameter of a circular pond is 42 m. What is its circumference? Use 3.14 for

.

9-2 Perimeter and Circumference
Example 9
The diameter of a circular spa is 14 m. What is its circumference? Use 22/7 for

.

9-2 Perimeter and Circumference
Lesson Quizzes
Standard Lesson Quiz
Classroom Activity

9-2 Perimeter and Circumference
Lesson Quiz
Find the perimeter.
1.
8 m
2.
10 m
6 m
12 m
45 m
9 m
10 in.
8 in.
36 in.
3. What is the circumference of a circle with a a radius of 8 inches? Use 3.14 for  .
50.24 in.
4. If a guardrail is to be placed around the edge of a circular swimming pool with a diameter of
21 ft, how many feet of railing will be needed?
 .
66 ft