[inner and outer circle] Showing the inner and outer circle of a triangle. #manim #geometry #triangle #circle

20240406_inoutcircle.py

class inoutcircleTriangle(Scene):
    def construct(self):
        triangle = VMobject()
        incirc   = VMobject()
        outcirc  = VMobject()
        for i in range(5):
            A = np.array([np.random.uniform(-5,5),np.random.uniform(-3,3),0])
            B = np.array([np.random.uniform(-5,5),np.random.uniform(-3,3),0])
            C = np.array([np.random.uniform(-5,5),np.random.uniform(-3,3),0])
            a = np.linalg.norm(B-C)
            b = np.linalg.norm(A-C)
            c = np.linalg.norm(A-B)
            s = (a+b+c)/2
            I = (a*A + b*B +c*C)/(a+b+c)
            r = np.sqrt(((s-a)*(s-b)*(s-c))/s)
            ocenter = (a**2*(b**2+c**2-a**2)*A + b**2*(c**2+a**2-b**2)*B + c**2*(a**2+b**2-c**2)*C)/(a**2*(b**2+c**2-a**2) + b**2*(c**2+a**2-b**2) + c**2*(a**2+b**2-c**2))
            oradius = np.linalg.norm(A-ocenter)
            self.play(Transform(triangle, Polygon(A,B,C)))
            self.play(Transform(incirc, Circle(radius=r,color=RED).move_to(I)))
            self.play(Transform(outcirc, Circle(radius=oradius,color=YELLOW).move_to(ocenter)))
            self.wait()
            
# https://en.wikipedia.org/wiki/Incircle_and_excircles
# https://en.wikipedia.org/wiki/Circumcircle

readme.md

https://en.wikipedia.org/wiki/Incircle_and_excircles

https://en.wikipedia.org/wiki/Circumcircle