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given, csa : tsa of cylinder = 1:2
          2πrh / 2πr(r+h)  = 1/2
             h/(r+h) = 1/2
 by cross multiplication, we get
             2h = r+h
             2h-h = r
therefore h=r
by calculating, we get height is equal to radius. then ratio of their height and radius is      
     height of cylinder : radius of cylinder = 1:1
1 5 1
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ratio of curved surface area(c.s.a) and total surface(t.s.a) of a right circular cyclinder = 1:2
2πrh / 2πr(r+h)  = ½
h/(r+h) = ½ (2πrh on the both sides will be cancelled)
2h = r+h (by cross multiplying)
2h-h = r
therefore h=r

therefore height of cylinder = radius of cylinder

                 = 1:1