Question

Calculate the area of the circle whose diameter is 6 km. Note: you will need the radius. Please round to the nearest square kilometer.

my answer was
first to find the radius we divide the diameter in half

6/2= 3

so the radius is 3 so now we times that by



x 32 =



then i simlifly it to

9



then i subsitute 3.14 for



9 x 3.14 = 28.2



the area is exactly 9 or about 28.8 centimeters

but my teacher says i need to rounded and the units should be squared

Answer 1

pi (3)^2 is right for the area of the circle

Answer 2

the radius of a circle is 1/2 the diameter, so the radius of this circle is 3.

The formula for the area of a circle is:
A = πr^2 where r is the radius

approximating π as 3.14,
Area = 9(3.14) = 28.26 sq. km.

I do not know what you mean by "round to the n".

Answer 3

the area is exactly 9pi; the approximation is then 28.2

Answer 4

oh, units are what you used to measure with :) centimeters ... and area is always ^2

Answer 5

ugh, km not cm

Answer 6

... byt the time i got to readin gto the end i had forgotten what it started with ;)

Answer 7

i think @amistre mean't this
The diameter is related to the radius by,

r = d/2

Therefore, our radius is,

r = 6/2 = 3km

The area of a circle is then,

A = pi*r^2 = pi*(3^2) = 28.3 km^2

Answer 8

thanks you guys are the best :)

Answer 9

Welcome! :)