Find the interest rate needed for an investment of $9,000 to quadruple in 15 years if interest is compounded quarterly. (round your answer to the nearest hundredth of a percentage point.)

answer: the angel abc is 30°,and the abc is a triangle where the angel bac is 90°

so ac is the half of 24=12ft,and from the pythagorean theorem we find ba

ba=√bc^2-ac^2=√576-144=√432=12√3ft

so bac is 12+12√3=12(1+√3)ft

i dont know the answer but here's a picture of a dog