# Math homework help?

Question:Ok well my math teacher gave us some homework and it has a problem with circumference and area. I know how to do area, but not circumference. Can somebody teach me how to do it? Thx in advance!

Circumference is pi (3.14) times diameter (straight line across the circle, splitting it into two equal portions).

If you do not have the diameter, you use the radius, which is half of the diameter. So if the diameter is 20, the radius is 10; thus, to solve with radius: 3.14 x r x 2
c = pi * d or
c = pi * 2r

c = circumference
d = diameter
circumference of a circle= 2 x pi x radius
OR
pi x diameter
circumference=c
pi= 3.14

so, c=pi*d

D would be the half of the radius. With a ruler measure how much width the circle has in its mid point. Divide that measure by half and you get d.

Now the only thing you gotta do is substitute
c=3.14*d value

Lets say you've got a circle. (When you measure it with your ruler imagine as if there was a line dividing the circle in half and that you were measuring that line) So, the radius is 8. d value is 4.

Now, I wanna get the circumference.

so;

c=pi*d
c= 3.14 * 4
c= 12.56
The circumference of a circle is the distance around it just like the perimeter of a rectangle is the distance around the rectangle.

The circumference of a circle is just a bit more than 3 times the distance across. If diameter = 6, then circumference is about 18.

Actually the circumference is approximately 3.14 times the diameter not just 3. And, 3.14 is known as pi.

The formula is (pi)(d) pie times the diameter. Answer is always in feet, inches, etc.(not square inch, etc. because that is how you label area.
You have to be a bit more specific.Area and circumference of what?. I will just give you a few formulas

Square - circumference(4xlength), area(length raised to the power of 2)
circle - circumference(2x pie x radius), area(pie x the square of the radius)

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