the sides of a triangle are 80 cm, 100cm, and 140 cm. determine the radius of the inscribed circle

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- Nov 4th 2010, 12:10 AMaeroflixinscribed circle
the sides of a triangle are 80 cm, 100cm, and 140 cm. determine the radius of the inscribed circle

- Nov 4th 2010, 06:16 AMearboth
1. Draw a sketch.

2. Calculate the area of the triangle: Use Cosine rule to determine one interior angle (i.e. ) of the triangle, for instance the angle opposite the side a. Then the area is:

3. The center of the inscribed circle is the common vertex of three interior triangles whose area is:

- Nov 6th 2010, 12:35 AMearboth