Question 1198553
Total surface area of cone = pir^2+pirl = pir(r+l)

Lateral surface area = pi r l

Given condition 

pir(r+l) = 3/2 * pi r l

(r+l) = 3/2* l


2r+2l = 3l

l=2r

6 = 2r
 r=3 inches