math
posted by tatyana on .
The dimensions of circle B are three times the dimensions of circle A. The area of circle A is 49 cm2.
What is the area of circle B?

areas of circles are proportional to the square of their radii
so
49/area of B = r^2/(3r)^2 = 1/9
area of B = 9(45) or 405 cm^2