If the radius of a circle is increased by 20% then the area is increased by:
a) 44% b) 120% c) 144% d) 40% e) None of the above

• Radius is increasd by 20% so new r=1.2r, New area=1.44pi(r^2) increase in area .. 0.44* 100 = 44%
• 13 years agoHelpfull: Yes(36) No(5)
• initially A=pi*r2
  now R2=120/100r
  then area=Pi*(120R/100)2
  area=144R/100
  that is area increases from 100 to 144=increase in area=44%
• 13 years agoHelpfull: Yes(19) No(4)
• let say radius = 10
  area = 314
  
  new radius = 12
  new area = 452.16
  
  increment = (452.16-314)/314*100 = 44%
  
  Ans - a) 44%
• 13 years agoHelpfull: Yes(16) No(8)
• Shortcut trick for such type of question
  
  a(a+200)/100 %
  
  where a is Increased radius
  
  after put the value of a
  Answer is = 44 %
• 8 years agoHelpfull: Yes(5) No(0)
• increased by 44%
• 9 years agoHelpfull: Yes(3) No(1)
• let initially the area is 100. as r increases by 20%,so the area increases 20% and 20% successively.
  so we can use the formula a+b+ab/100.here a=b so 20+20+(20*20)/100=0.44=44%
• 8 years agoHelpfull: Yes(1) No(0)
• increased by 44%
• 6 years agoHelpfull: Yes(0) No(0)
• percentage increase = X+Y+((XY)/100)
  20+20+((20*20)/100) = 44%
• 5 years agoHelpfull: Yes(0) No(0)