# PMAT-477 (R8): Python float (f64). Float arithmetic is plain infix
# (IEEE-754, no checked/overflow); `/` is true division (not floor).
def lerp(a: float, b: float, t: float) -> float:
return a + (b - a) * t
def average(x: float, y: float) -> float:
return (x + y) / 2.0
def scale(xs: float, k: float) -> float:
r = xs * k
return r