Circle 1, circle 2, and circle 3 have the same center and have radii, respectively, of r1 cm, r2 cm, r3 cm, where r1 < r2 < r3. let a1 be the area of circle 1, let a2 be the area of the region within circle 2 and outside circle 1, and let a3 be the area of the region within circle 3 and outside circle 2, where all areas are in cm2. what are the values of \small \frac{a_{1}}{a_{2}} and \small \frac{a_{2}}{a_{3}} ?