1. **State the problem:** We need to determine which of the given statements about a circle's radius, diameter, and circumference are true. 2. **Recall key formulas and definitions:** - Diameter $d$ is twice the radius $r$: $$d = 2r$$ - Circumference $C$ is given by: $$C = 2\pi r = \pi d$$ 3. **Evaluate each statement:** - "The radius of a circle is twice its diameter." Using $d = 2r$, rearranged gives $r = \frac{d}{2}$, so radius is half the diameter, not twice. **False**. - "To find the diameter of a circle, divide its circumference by $\pi$." Since $C = \pi d$, dividing both sides by $\pi$ gives $\frac{C}{\pi} = d$. **True**. - "The circumference of a circle is greater than its diameter." Since $C = \pi d$ and $\pi \approx 3.14 > 1$, $C > d$. **True**. - "The circumference of a circle is twice its radius." Since $C = 2\pi r$, and $2\pi r \neq 2r$, this is **False**. - "To find the diameter of a circle, multiply its radius by two." By definition, $d = 2r$. **True**. 4. **Summary of true statements:** - To find the diameter of a circle, divide its circumference by $\pi$. - The circumference of a circle is greater than its diameter. - To find the diameter of a circle, multiply its radius by two. 5. **Final answer:** The true statements are the 2nd, 3rd, and 5th.