a semi circle is drawn with ab as diameter. from c a point on ab a line perpendicular toa ab is drawn meeting the circumference at D. given that ac=2cm and cd =6cm the ared of the semicircle is sq cm
a. 50pi
b. 55pi
c. 31pi
d. 82pi

• a. 50pi
  from two similar tri(ADC) & tri(BDC),
  ac/cd=cd/bc
  bc= cd^2/ac
  = 6*6/2
  =18
  ab= ac+bc= 2+18= 20cm
  radius, r= 20/2=10cm
  area of the semi circle= pi* r^2/2= 50pi
  
• 9 years agoHelpfull: Yes(29) No(4)
• suppose e be the centre
  then ce= radius- 2
  cd=6
  (radius)^2 =6^2 + (radius -2)^2
  radius = 10
  area of semicircle =pi(radius)^2/ 2 = pi * (100)/2 =50pi
• 9 years agoHelpfull: Yes(12) No(0)
• AC=2 cm, CD=6 cm, OA=OD(diameter) , find OD^2=CD^2+OC^2 ,or OA^2=(OA-AC)^2+CD^2
  OA^2=(OA-2)^2+6*6, or OA^2-(OA-2)^2=36, or (OA-OA+2)(OA+OA-2)=36, or2(2OA-2)=36
  4(OA-1)=36,or OA-1=9, Or OA=10 this is radius of semicircle.
  so area of semicircle=1/2*pi*r^2=1/2*pi*10*10 =50pi or 50*3.14=157
  area of semicircle =50pi, or 157 is a correct ans
• 9 years agoHelpfull: Yes(2) No(0)
• ans- 50Pi
• 9 years agoHelpfull: Yes(1) No(1)
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• 9 years agoHelpfull: Yes(0) No(0)