1. **Problem:** Find the circumference of a circle with diameter 16 cm in terms of $\pi$. 2. **Formula:** The circumference $C$ of a circle is given by $$C = 2\pi r$$ where $r$ is the radius. 3. **Step 1:** Since diameter $d = 16$ cm, radius $r = \frac{d}{2} = \frac{16}{2} = 8$ cm. 4. **Step 2:** Substitute $r = 8$ cm into the formula: $$C = 2\pi \times 8 = 16\pi$$ 5. **Answer:** The circumference is $16\pi$ cm. 1. **Problem:** Find the circumference of a circle with radius 3 m in terms of $\pi$. 2. **Formula:** The circumference $C$ of a circle is $$C = 2\pi r$$ 3. **Step 1:** Given radius $r = 3$ m. 4. **Step 2:** Substitute $r = 3$ m: $$C = 2\pi \times 3 = 6\pi$$ 5. **Answer:** The circumference is $6\pi$ m.