Kelly reduced the size of a portrait to have a width of 10 inches. if she used a scale of 1 inch : 2 inches, what was the width of the original portrait?

So basically you use the ratio they have given you. You either multiply by 2 if image is enlarged or divide by 2 if it is reduced. (Keep in mind I got the 2 from your ratio : 1inch : 2inches) Therefore the find the original width, you multiply 10 by 2, giving you 20 inches.

hello from mrbilldoesmath!

answer:   x^2 + y^2 = 1024

discussion:

the equation of a circle with center (h,k) and radius "r" is

(x-h)^2 + (y-k)^2 = r^2.

in our case

(x-0)^2 + (y-0) ^2 = 32^2 = 1024

you,

mrb