So,
Here we have the following circle:
Given that the radius of the circle is 12cm, we can say that the segments PN and NQ measure both 12cm.
The radius of the circle is the distance from the center of the circle to any point of it. The diameter, is two times the radius, so:
![\begin{gathered} D=2(\text{radius)} \\ D=2(12cm) \\ D=24\operatorname{cm} \end{gathered}]()
Then, the diameter of the circle measures 24 cm.
To find the circumference, we just use the formula:
![C=2\cdot\pi\cdot r]()
Where pi is 3.14 and r is the radius.
So, we just replace:
![\begin{gathered} C=2\cdot3.14\cdot12\operatorname{cm} \\ C=75.36\operatorname{cm} \end{gathered}]()
Therefore, the circumference of the circle measures 75.36cm.
Finally, to find the area, we could use the formula for it:
![A=\pi\cdot r^2]()
Replacing the values:
![\begin{gathered} A=3.14\cdot(12\operatorname{cm})^2 \\ A=3.14\cdot144\operatorname{cm} \\ A=452.16\operatorname{cm} \end{gathered}]()
Therefore, the area measures 452.16cm.