What is the formula for area of a circle?

Agraphic designer created a logo on eight and a half by 11 inch paper. in order to be placed on a business card, the logo needs to be one and 7/10 inches by 2 and 1/5 in. what is the scale factor of the dilation

If 2(a^2+b^2)=(a+b)^2 then, > a+b=0, > ab=0, > a=b, > 2a=b

Given a: b and b: c, find a: b: c. write the ratio in simplest form. a: b=6: 10 and b: c=21: 33