How do you find the circumference and the area of a circle with diameter 6m?

1 Answer
Sep 28, 2015

Area of circle = #pir^2# or #pi (d/2)^2#
Circumference of circle = #pid#
For a circle with diameter #6#m this becomes #A~=28.27m^2# and #C~=18.85m#

Explanation:

The constant #pi ~=3.14159# is the ratio of the circumference of a circle to its diameter (or equivalently to twice it's radius).

#C=pid = pi2r#

That same value, #pi#, is also the ratio of the the area of a circle to the square of its radius

#A=pir^2#

Plugging the given diameter (or diameter divided by 2 for the radius) into these equations gives the required results.