Multiple choice

ABC is a right angled triangle with BC = 6 cm. and AB = 8 cm. A circle with centre O is inscribed in Δ ABC. Find the radius of the circle. ABC एक समकोण त्रिभुज है जिसमें BC = 6 सेमी. और AB = 8 सेमी. है, त्रिभुज ABC में एक अंतः वृत्त O केन्द्र का है, तो उस वृत्त की त्रिज्या ज्ञात कीजिए।

  1. 1 cm./सेमी.

  2. 2 cm./सेमी.

  3. 3 cm./सेमी.

  4. 4 cm./सेमी.
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B Correct answer
Explanation

In a right triangle with legs 6 and 8, the hypotenuse is 10 (6-8-10 Pythagorean triple). For an incircle in a right triangle, r = (a + b - c)/2 = (6 + 8 - 10)/2 = 2 cm. Alternatively, area = (1/2) × 6 × 8 = 24, semiperimeter = 12, and r = Area/s = 24/12 = 2.

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