Question

How do you find the circumference and area of the circle with a diameter of 9 inches?

Answer 1

Hint: To order to determine the circumference and area of the circle ,find radius using $ r = \dfrac{{diameter}}{2} $ and use the formula of area of circle = $ \pi {r^2} $ and circumference of circle $ = 2\pi r $ to find the required answer

Complete step-by-step answer:
Let we are given a circle C having radius $ r $ and diameter as $ d $
According to question, diameter of the circle $ d = 9\,in $
So first we have to find the radius of the circle using the given diameter as the radius is always the half of the diameter of the circle
 $
  r = \dfrac{d}{2} \\
  r = \dfrac{9}{2} \\
  r = 3.5\;in \;
  $
Now to calculate the area of the circle use the formula area= $ \pi {r^2} $
Putting the value of $ r = 3.5\;in $ in the formula
Area of Circle =
 $
   = \pi {r^2} \\
   = \pi {(3.5)^2} \;
  $
Taking value of $ \pi = 3.14 $
 $
   = (3.14){(3.5)^2} \\
   = (3.14)(12.25) \\
   = 38.465\,i{n^2} \;
  $
Thus, the Area of circle is equal to $ 38.465\,i{n^2} $
Now calculating the circumference of the circle using formula circumference of circle $ = 2\pi r $
Circumference of circle=
  $
   = 2\pi r \\
   = 2(3.14)(3.5) \\
   = 21.98\;in \;
  $
Therefore, Area of circle equal to $ 38.465\,i{n^2} $ and Circumference is equal to $21.98\;in $
So, the correct answer is “Area of circle equal to $ 38.465\,i{n^2} $ and Circumference is equal to $ 21.98\;in $ ”.

Note: 1.Area of Circle: The Area or the region bounded by the circle on the 2D plane is known as Area of Circle
2.Circumference of Circle: It is the length of the distance around the circle is called circumference.