The circumference of a circle is 8pi. whats its area?? URGENT?also what is the slope intercept of 7x-21y=14?

Question

the circumference is 8 PI what is the area of it urgent please help also what is the slope {rise,run} of 7x-21y=14.

Answer 1

1) The circumference of a circle can be found by the formula C-pi(d) where d is the diameter.  So if the circumference is 8pi then the diameter is 8.  If the diameter of the circle is 8 then the area is half of that 4.

The are of a circle is found with the formula A=pi(r)^2

so to solve

A=pi(4)^2

A=16pi

A=50.24

2) We need to put the formula in slope intercept form y=mx+b.  m is the slope and b is the y-intercept.

so to solve:

7x-21y=14

-21y=-7x+14

y=(1/3)x-2/3

so the slope if 1/3

the y intercept is at -2/3

Answer 2

8*pi=2*pi*r

4=r

a=pi*r^2

a=16*pi

(1,3) for the slope bc

21y=7x-14

and 7/21=1/3

Answer 3

2(pi)r=8(pi)

r=8(pi)/2(pi)

r=4

Area = (4) squared * pi

=(16)pi

21y= 7x - 14

y=1/3x - 2/3

Answer 4

the slope is 1/3 or (1,3)

the radius of your circle is 4 so the answer is 16pi

Answer 5

Circumference = 2 PI r  

2 PI r = 8 PI

PI r = 4 PI

r = 4

A = PI r^2

A = PI 4^2

A = 16 PI

Slope is 1/3

7x-21y=14 convert to y=mx+b

-21y=-7x+14

-3y=-x+2

y=x/3-(2/3)