The area of a circle is 49 cm2. find the circumference of the circle.

(note: make sure you are showing the formulas you use to answer the question and how the numbers fit into the formulas).

i just need a step by step, .

C = 14 sqrt(pi)

Step-by-step explanation:

The formula for area of a circle is

A = pi r^2

49 = pi r^2

Divide each side by pi

49/pi = r^2

Take the square root of each side

sqrt(49/pi) = sqrt(r^2)

sqrt(49/pi) = r

Now we need to find the circumference

C = pi * 2 *r

C = pi * 2 * sqrt(49/pi)

C = pi * 2 *7/sqrt(pi)

We need to get rid of the qrt(pi) in the denominator) so multiply by sqrt(pi)/sqrt(pi)

C = pi * 2 *7/sqrt(pi) * sqrt(pi)/sqrt(pi)

C 14 pi* sqrt(pi)/pi

The pi in the numerator and denominator cancel

C = 14 sqrt(pi)

there are lots of ways.   pick's theorem tells us if the vertices are lattice points the area a is

a = b/2 + i - 1

where b is the number of boundary lattice points and i is the number of interior lattice points.

in the figure i count b=16, i=50 so

a = 8 + 50 - 1 = 57

let's try the shoelace formula.   the area is half the sum of the cross products of the sides.  

a(-2,6)   -2(2)-6(-5) = 26

b(-5,2)   -5(-3) - 2(-2) = 19

c(-2,-3) -2(-3) - (-3)(4) = 18

d(4,-3)   4(3) - (-3)(5) = 27

e(5,3)   5(3) - 3(1) = 12

f(1,3)     1(6) - 3(-2) = 12

a(-2,6)

each of the cross products is twice the area of the triangle with the associated side and one vertex the origin. so the area of abo=26/2=13.

area = (1/2) (26 + 19 +   18 + 27 + 12 + 12) = 57

that checks!

gdp is the best phrase!