Transcript Circumference and Area of a Circle

Circumference & Area
of a Circle
MA.6.4.1: Estimate the circumference and area of a circle
Period 4
Definition
Circumference is the distance around a
circle or the perimeter.
Formula = Pi x diameter
Area is the measure of the amount of
surface enclosed by the boundary of a
figure.
Formula = r x r x pi
Example: Circumference
Formula = Diameter x Pi
Diameter = 2 in.
Pi = 3.14
2 x 3.14 = 6.28 in.
2 in.
Example: Area
Formula = radius x radius x Pi
Radius = 5 cm.
Pi = 3.14
5 cm.
5 x 5 x 3.14 = 78.5 sq. cm.
Problem
Kristle wanted to find the area and the
circumference of a circle with a diameter
of 26 in. Find the area and circumference
of her circle.
26 in.
Solution
The area of Kristle’s circle is 530.66 in.
because if the diameter is 26 in. then the
radius must be 13 in. (26/2=13)
13 x 13 = 169
169 x 3.14 = 530.66 sq. in.
The circumference of Kristle’s circle is
81.64 in. because 26 x 3.14 = 81.64
Credits
I give credit to my parents for giving me support……
I also give credit to my math teacher,
Mr. Imamura
for teaching me what the circumference and area is and the formula
for each……
I also give credit to my friends (Kristle mostly) for helping me use
Microsoft PowerPoint:
Definition from Connected Mathematics.
Hope you enjoyed my fantabulous presentation on the circumference
and the area of a circle.