If radius of a cone is increased by 20% and its slant height is made double, then how much % will the area of its curved surface be increased ?

• 140%
  
  If r=radius, l=slant height, then Curved surface Area of cone=Pi*r*l
  New radius=1.2r , slant height=2l, so new Curved surface Area=Pi*1.2r*2l=2.4*Pi*r*l
  So % increase in curved surface area=(2.4*Pi*r*l - Pi*r*l)*100/(Pi*r*l)= 140
• 8 years agoHelpfull: Yes(1) No(0)