Question

Find the exact area of a circle with diameter of 10 units.

10pi
100pi
5PI
25Pi

Answer 1

d/2=r
area=pir^2
d=10
d/2=10/2=5

area=pi5^2
area=25pi
answer is 4th option

Answer 2

D.
`25\pi\text{ units}^2`

Explanation:

We have been given that diameter of a circle is 20 units.

To find the area of our given circle we will use area of circle formula.

`\text{The area of circle}=\pi r^2`, where r represents radius of circle.

let us find the radius of our given circle by dividing diameter by 2 as diameter is 2 times radius.

`\text{Radius of circle}=(10)/(2)`

`\text{Radius of circle}=5`

Upon substituting r=5 in area of circle formula we will get,

`\text{The area of circle}=\pi*\text{(5 units)}^2`

`\text{The area of circle}=\pi*25*\text{ units}^2`

`\text{The area of circle}=25\pi\text{ units}^2`

Therefore,the exact area of our given circle is
`25\pi` square units and option D is the correct choice.