PowerPoint Presentation
Defining SuccessEasy As Pie?
Defining Success! Easy as pie?1In this lesson we will:M.7.G.4
Discuss the formulas for the area and circumference of a circle and
use them to solve problems Discover an informal relationship
between the circumference and area of a circle
In this lesson we will discuss the formulas for the area and
circumference of a circle and use them to solve problems. We will
also discover an informal relationship between the circumference
and area of a circle.
2Real World ExampleLets go back to Justin and his house
building. We know that he is drilling cylindrical holes using an
auger. Justin wants to know the area of the cross section to make
sure the wooden pole will fit into the drilled hole.Remember, the
formula for the area of a circle is A = pi x r2We will use 3.14 for
pi. Remember, the radius (r) is HALF the diameter! Round your
answer to the nearest hundredth.The diameter of the hole is 0.5 m.
A = 3.14 * (0.25)2 A = 3.14 * 0.0625A = 0.20 mThe area of the cross
section is 0.20 meters.
Real World Example: Lets go back to Justin and his house
building. We know that he is drilling cylindrical holes using an
auger. Justin wants to know the area of the cross section to make
sure the wooden pole will fit into the drilled hole. Remember, the
formula for the area of a circle is A = pi x r2We will use 3.14 for
pi. Remember, the radius (r) is HALF the diameter! Round your
answer to the nearest hundredth.The diameter of the hole is 0.5
meters. We are solving the equation 3.14 * (0.25)2 The first thing
we will do is square 0.25, this equals 0.0625. Next we will
multiple 0.0625 by 3.14. Our final answer is 0.20 meters. So, the
area of the the cross section is 0.20 meters.
3By the end of this lessonYou will be able to:Find the
circumference of a circle using the area of the circleFind the area
of a circle by using the circumference of the circle
By the end of this lesson, you will be able to find the
circumference of a circle using the area of the circle and find the
area of a circle by using the circumference of the circle.
4Lets Get Started!You will soon be able to:Use the circumference
of a circle to find the areaUse the area of a circle to find the
circumference
Lets get started! You will soon be able to use the circumference
of a circle to find the area. You will also use the area of a
circle to find the circumference.5
