If a wire is bent into the shape of a square, then the area of the square is 81sqcm.When wire is bent into a semi-circular shape,then the area of the semi-circle will be?

• a^2=81
  so a=9
  length of wire=4*a=4*9
  if semicircle made with that then the circumference will be (pi*r+2*r)=36
  hence r=36/(pi+2)
  so area of semicircle will be pi*r^2/2=pi*36/(2*(pi+2)^2)=77.0068
• 9 years agoHelpfull: Yes(17) No(3)
• 
  
  Total length of the wire = 4*(route of 81) =36
  
  so perimeter of the semicircle = ( pi*r + 2*r ) = 36;
  then; r= 7.
  
  So Area = 1/2 * (pi*r*r) = 77
• 9 years agoHelpfull: Yes(14) No(1)
• a^2=81
  a=9
  
  now, perimeter of the sqr=4*a=4*9=36= total length of the wire
  
  36=perimeter of the semi circle=pi*r
  r=36/pi
  
  area=pi*36*36/pi*pi*2
  =206.3 sq unit.
• 9 years agoHelpfull: Yes(4) No(14)
• area of square = 81
  so side of square = 9
  so length of wire = perimeter of square
  =9*4
  =36
  now
  perimeter of semi circle = PI*r +2r
  = r(pi+2) =36 (since pi+2=5.14)
  so r = 7.003
  area of semi circle = 1/2 * PI r*2
  =154/2
  77
• 9 years agoHelpfull: Yes(2) No(1)
• Very sorry for the mistake.
  the answer will be 77 sq cm..
• 9 years agoHelpfull: Yes(2) No(0)
• 
  
  KOUSHIKI , Pls do expln.
• 9 years agoHelpfull: Yes(1) No(0)
• area of square is given=81sqcm then a^2=81 so a=9
  perimeter of square=4*9=36
  so total length of the wire==36cm
  now length of semi circle=pi*r+2r
  so pi*r+2r=36
  r=7
  area of semicircle=77
• 9 years agoHelpfull: Yes(1) No(0)
• Answer will be 206.36 sq unit..
• 9 years agoHelpfull: Yes(1) No(4)
• area of square is given=81sqcm then a^2=81 so a=9
  perimeter of square=4*9=36
  so total length of the wire==36cm
  now length of semi circle=pi*r+2r
  so pi*r+2r=36
  r=7
  area of semicircle=77
  
• 9 years agoHelpfull: Yes(1) No(0)
• AREA=pi*R*R/2
  R=4.5
• 9 years agoHelpfull: Yes(0) No(6)
• s^2=81
  4s=36
  2r+pi*r=36
  r=7.00
  (pi*r^2)/2=76.96
• 9 years agoHelpfull: Yes(0) No(1)
• Here the length of the wire is same.As the wire is bent into a shape of square of area =81cm2and side2=area of squareso side =81−−√=9×9−−−−√=9cmHence side of the square =9cmand it has four sides, so length of the wire used is 9×4=36cmAnd circumference of a circle =2πrso circumference of semi−circle=2πr/2=πrthis circumference of semi−circle=length of the wireHence πr =36cm⇒r=36/πAs Area of semicircle =πr2/2 Area of semicircle=π(36)22π2=(36*36)/2pi = 206.3(ans)
• 9 years agoHelpfull: Yes(0) No(4)