- - - - -_3n - - - - - Circle A has a radius of and circle B has a radius 129n of, where n is a positive constant. The area of circle B is how many times the area of circle A?
Correct answer: D (parsed from the explanation — this source omits an answer key for this item)
Explanation
=r 2 Choice D is correct. The area of a circle can be found by using the formula A r , where A is the area and r is the radius of the circle. It’s given that the radius of =r 2 circle A is 3n. Substituting this value for r into the formula A r gives =r 3 2 9r 2 129 A ^ nh , or n . It’s also given that the radius of circle B is n. Substituting =r 2 =r 129 2 16,641r 2 this value for r into the formula A r gives A ^ nh , or n . Dividing 16,641r 2 1,849 n the area of circle B by the area of circle A gives 9r 2 , which simplifies to . n 1,849 Therefore, the area of circle B is times the area of circle A. Choice A is incorrect. This is how many times greater the radius of circle B is than the radius of circle A. Choice B is incorrect and may result from conceptual or calculation errors. Choice C is incorrect. This is the coefficient on the term that describes the radius of circle B.
Loading…
Searched on YouTube by topic, not by question text. Open this search on YouTube →
Extracted from PDF layout: equations, figures and tables do not survive intact. Use the original PDFs for anything the text renders poorly. SAT® is a trademark registered by the College Board, which is not affiliated with and does not endorse this project.