Geometry and TrigonometryEasyDiameter from a radius
Geometry and Trigonometry practice question
A circle has a radius of 4.5 centimetres. What is the length, in centimetres, of its diameter?
Answer: 9
The diameter is twice the radius: 2 × 4.5 = 9.
Common wrong answers
- If you answered 2.25
- 2.25 halves the radius instead of doubling it.
- If you answered 20.25
- 20.25 is the radius squared.
- If you answered 14.1
- 14.1 is about π × 4.5, a slip toward the circumference.
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