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What will be the increase in area of circle if its radius is increased by 40%?
Area (A1) of circle with radius r is =  ?. r2
when radius increase by 40%, that means new radius become, = [r + 40% * r]
= [ r + (40/100)* r ]
= [ r +(2/5)*r]
= (7/5) *r or, (7r)/5
now Area of circle with radius (7/5)*r is,
A2=  ?* [(7/5)*r] 2 or,  ?* [(49/25)*r2]
now increase in Area of circle is A2 - A1 , = [? * (49/25) * r2 ] - [?* r2] 
= (24/25) * ? * r2 = (24/25) *A1, so the Area of the circle is increased by (24/25) or 0.96 %


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