A circle has radius 7 cm. Its diameter is:

**The reasoning** The diameter of a circle is simply **twice the radius**. This is a fundamental property of circles. The formula is: **Diameter (d) = 2 × radius (r)** Given: radius = 7 cm So: d = 2 × 7 = **14 cm** Think of it visually: the radius stretches from the center to the edge. The diameter goes all the way across, passing through the center — so it covers the radius twice (once on each side of the center). **Why the wrong options tempt you** - **A (7 cm)** – You might confuse diameter with radius itself. They're different! - **C (21 cm)** – You calculated 3 × radius instead of 2 × radius. Maybe you mixed it up with another formula. - **D (49 cm)** – This is 7², which would be for finding area (πr²), not diameter. Wrong formula entirely. **Quick takeaway** **Diameter is always double the radius** — just remember "Di-ameter = 2 times!" and you'll never mix them up again.