Calculate the perimeter of the following shapes

The perimeter $P$ of a triangle with side lengths $a$, $b$, and $c$ is given by:

$$P = a+b+c$$

$$P = 12 \text{ cm}$$

The perimeter of the triangle is $\boxed{\text{12 cm}}$.

The circumference $C$ of a circle with radius $r$ is given by:

$$C = 2\pi r$$

$$C = 6\pi \text{ cm}$$

Using $\pi \approx 3.14159$:

$$C \approx 6 \times 3.14159 \text{ cm}$$ $$C \approx 18.85 \text{ cm}$$

The perimeter (circumference) of the circle is $\boxed{\text{6\pi cm}}$ or approximately $\boxed{\text{18.85 cm}}$.