What is the radius of the circle?
A triangle ABC with sides AB=15\text{ cm}, BC=9\text{ cm}, CA=12\text{ cm} is inscribed in a circle.
- A. 4.5\text{ cm}
- B. 6\text{ cm}
- C. 7.5\text{ cm} ✓
- D. 15\text{ cm}
Correct Answer: C. 7.5\text{ cm}
Explanation
Since \triangle ABC is a right-angled triangle, its hypotenuse AB serves as the diameter of the circumscribed circle. The radius is \frac{AB}{2} = \frac{15}{2} = 7.5\text{ cm}.
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