1. **Problem:** Draw a triangle with inradius 3 cm and two angles 50° and 70°. 2. **Formula and rules:** - The sum of angles in a triangle is 180°. - The third angle is $180° - 50° - 70° = 60°$. - The inradius $r$ relates to the triangle's area $A$ and semiperimeter $s$ by $r = \frac{A}{s}$. 3. **Steps to draw:** - Draw angle 50° at point A. - Draw angle 70° at point B. - The intersection of these rays forms the triangle with the third angle 60° at point C. - Use the inradius 3 cm to locate the incircle tangent to all sides inside the triangle. 4. **Explanation:** - The inradius is the radius of the circle inscribed inside the triangle touching all sides. - Constructing the triangle with given angles ensures the shape. - The incircle can be drawn by finding the incenter (intersection of angle bisectors) and drawing a circle of radius 3 cm. **Final answer:** A triangle with angles 50°, 70°, 60° and an incircle of radius 3 cm can be constructed by drawing the two angles and locating the incenter to draw the incircle of radius 3 cm.