Given:
A circle with diameter 9 cm.
To find:
The area of the circle.
Solution:
The area of a circle is:
...(i)
Where r is the radius.
We know that, the diameter of a circle is twice than its radius.
The diameter of the given circle is 9 cm.
![r=(9)/(2)](https://img.qammunity.org/2022/formulas/mathematics/high-school/h45wwbj7ajoi1phmrxf6cudgllvrzxl6j4.png)
![r=4.5](https://img.qammunity.org/2022/formulas/mathematics/high-school/p9tziwe5x0bwlwyx9tbiuncr7jw04zy1s1.png)
Substituting
in (i), we get
![A=(3.14)(4.5)^2](https://img.qammunity.org/2022/formulas/mathematics/high-school/ooztwpq9lgxzugezb31daobnqo4fihbgcn.png)
![A=(3.14)(20.25)](https://img.qammunity.org/2022/formulas/mathematics/high-school/s489wiprgsxsys652tulfe21vz5pzbsdwm.png)
![A=63.585](https://img.qammunity.org/2022/formulas/mathematics/high-school/vls2ecjyoidxdfyln5jsek4i6hbkix4cu6.png)
![A\approx 63.6](https://img.qammunity.org/2022/formulas/mathematics/high-school/ykrkfwl46wo2gzp3zbwgplvab7suginm2w.png)
Therefore, the area of the given circle is 63.6.