Multiple choice

The area of a triangle is 15 sq.cm and the radius of its incircle is 3 cm. Its perimeter is equal to

  1. 12 cm

  2. 20 cm

  3. 5 cm

  4. 10 cm
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D Correct answer
Explanation

The area of a triangle is given by Area = r * s, where r is the inradius and s is the semi-perimeter. Given Area = 15 and r = 3, we have 15 = 3 * s, so s = 5. The perimeter is 2 * s = 10 cm.

AI explanation

The area of a triangle can be expressed using its inradius and semi-perimeter with the formula Area = semi-perimeter * inradius. Given the area is 15 square centimeters and the inradius is 3 centimeters, we have 15 = semi-perimeter * 3, which gives a semi-perimeter of 5 centimeters. The full perimeter is twice the semi-perimeter, so the perimeter is 10 centimeters.

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