1. Area and Circumference
Circles
Area and Circumference

2. Vocabulary
Perimeter
The measure of the distance around a figure (distance around the outside)
Area
The number of square units needed to cover a surface or figure

3. Vocabulary Pi
Circumference divided by diameter

4. Vocabulary Circumference Perimeter of a Circle (outside of a circle)
Radius
Distance from edge of circle to the center
Diameter
Distance from one side of the circle to the other THROUGH THE CENTER

5. Circumference Circumference = perimeter of a circle C = 2(3.14)r
r = radius
C = circumference
C = (3.14)d
d = diameter

6. Area
A = 3.14r2 = 3.14 (4) 2 = 3.14(16) A = cm2
4cm

7. Diagram
circumference
diameter
radius

8. Helpful Information
Diameter = 2 x Radius d = 2r

9. Practice Problem
Clinton purchased a circular rug to cover part of a floor. The diameter of the rug is 8 feet. What area of the floor will the rug cover?

10. Rectangles and squares
Area and perimeter

11. SQUARE UNITS NORMAL UNITS
rectangles
Area: The space inside of a figure Perimeter: Distance around the outside To find area: Multiply length and width To find perimeter: Add up all of the sides OR
l = length
w = width
SQUARE UNITS
(cm2)
NORMAL UNITS
(cm)

12. SQUARE UNITS NORMAL UNITS
Squares
To find area, take a side and square it To find perimeter, take a side and multiply it by 4
s = side length
SQUARE UNITS
NORMAL UNITS

13. Practice problem
Dana has a rectangular garden that she wishes to fence in. If the dimensions of the garden are 15 feet by 13 feet, what is the minimum amount of fencing that she needs to enclose her garden?