def cercle(r:float):

    assert r>=0
    d=r*2
    p=r*2*np.pi
    s=np.pi*r*r
    return (d,p,s)

def coerf_droite(x1:float, y1:float, x2: float, y2:float):

    assert x1!=x2
    a=(y2-y1)/(x2-x1)
    b=x2-a*x1
    return (a,b)

def plus_petit(a: int, b: int, c: int):

    return min(a,b,c)