What is the radius of the in-circle of the triangle whose sides measure 5 12 and 13 units?
What is the radius of the in-circle of the triangle whose sides measure 5 12 and 13 units? Correct Answer 2
Sides are 5,12 and 13, so It is a right triangle as <math xmlns = "http://www.w3.org/1998/Math/MathML"><msup><mn>13</mn><mn>2</mn></msup><mo> = </mo><msup><mn>12</mn><mn>2</mn></msup><mo> + </mo><msup><mn>5</mn><mn>2</mn></msup></math>Therefore, area of the triangle = <math xmlns = "http://www.w3.org/1998/Math/MathML"><mfrac><mn>1</mn><mn>2</mn></mfrac><mo>×</mo><mn>12</mn><mo>×</mo><mn>5</mn><mo> = </mo><mn>30</mn></math>We have to find in - radiusarea of triangle = 5×r; perimeter, <math xmlns = "http://www.w3.org/1998/Math/MathML"><mi>S</mi><mo> = </mo><mfrac><mrow><mn>13</mn><mo> + </mo><mn>12</mn><mo> + </mo><mn>5</mn></mrow><mn>2</mn></mfrac><mo> = </mo><mfrac><mn>30</mn><mn>2</mn></mfrac></math> = 15;Thus, 30 = 15×rr = 2