Homework Help, Please?

Question

9. If the circumference of a circle is 1000 m. Then what is the Area and Radius of the circle?

10. If the Area of a circle is 10,000 miles squared. Then what is the circumference and radius of the circle?

12. 3C= 12 pi. What is the radius?

(C stands for circumference)

Answer 1

9.Formula for circ. of circle = 2πr

2πr=1000

r= 1000/2π

r=159.23

Formula for Area of circle = πr²

π(159.23)² =

79617.78

10. Follow # 9 above and you should get:

r = 56.43

c = 354.40

12. 3c = 12π

solve for c, c = 12π/3

c = 4π, and since the formula of circ = 2πr, then r must be 2.

Answer 2

To answer these three questions

you need to know two formulas:

Circle Circumference C = 2 pi r

and

Circle area A = pi r^2

And then plug in the different values

9.

1000 = 2 (3.14) r

r = 1000/6.28 = 159.24 m

10.

10,000 = 3.14 r^2

r^2 = 10,000/3.14 = 3,184.7

r = 56.433

12.

3C = 12 pi

C = 4 pi = 2 pi r

r = 2

I hope you get the hang of it from these three

examples.

The square root calculator in sources helps with the circle area

examples.

Answer 3

9)

1000 = 2pir

r = 1000/2pi = 159.155 m

area = pi r^2 = pi 159.155^2 = 79577.529 sq m

10)

10000 = pi r^2

r^2 = 3183.099

r = sqrt(3183.099) = 56.419 miles

Cir = 2 pi r = 2 pi 56.419 = 354.491 miles

12)

3C = 12 pi

C = 4 pi = 2 pi r

so r = 4 pi / 2 pi = 2

Answer 4

9.    A = pi(C/2pi)^2

A = (pi/4pi^2)C^2

A = (pi/4pi^2)(1000)^2

A = (1/4pi)(1000000)

A = 250000/pi

A = 79577.47155

r = C/2pi

r = 1000/2pi

r = 500/pi

r = 159.1549431

10.   C = 2pi*sqrt(A/pi)

        C = 2pi*sqrt(10000/pi)

        C = 2*sqrt(pi)*100

        C = 200sqrt(pi)

        C = 354.4907702

        r = sqrt(A/pi)

        r = sqrt (10000/pi)

        r = 100/sqrt(pi)

        r = 56.41895832

12.   3(2pi*r) = 12pi

        6pi*r = 12pi

             r = 2

Answer 5

Here are some equations that you seem to be missing.

c = 2 π r

A = π r^2