A′b′c′ is a dilation of triangle abc . what is the scale factor? enter your answer in the box. $\text{basic}$ $x$$y$$x^2$$\sqrt{ }$$\frac{x}{ }$ $x\frac{ }{ }$ $x^{ }$$x_{ }$$\degree$$\left(\right)$$\abs{ }$$\pi$$\infty$ note: images may not be drawn to scale. triangle abc is shown. side ab is labeled 9. side bc is labeled 9. side ca is labeled 18. triangle a prime b prime c prime is shown. side a prime b prime is labeled 4 and a half. side b prime c prime is labeled 4 and a half. side c prime a prime is labeled 9.