A girl of height 90 cm is walking away from the base of a lamp-post at a speed of 1.2 m/s.If the lamp is 3.6 m above the ground,What is the length of her shadow after 4 seconds ?

• let, length of her shadow is x.
  in 4 sec d gal cover d distance 4.8m
  now one rightangle made by d lamp & total dsnce covered by girl plus length of shadow and other is fored by hieght of the girl and her shadow.
  by comparing the 2 triangle we can write,
  (0.9/3.6)= (x/4.8)
  x=1.6m
  so the length of the shadow is 1.6m
  
• 12 years agoHelpfull: Yes(2) No(2)
• length of her shadow after 4 seconds =1.6m
  this is solved using concept of similar triangles.4.8/(3.6-.9)=x/.9
  x=1.6m
• 12 years agoHelpfull: Yes(1) No(1)
• @trisha ,the equation given in your soln is wrong. plz check.
  
• 12 years agoHelpfull: Yes(1) No(1)
• .
  . .
  . .
  . .
  . . .
  . . 0.9 . 3.6
  . . .
  . . . . . . . .
  x 4.8
  from the similar triangle,
  [.9/3.6]=[x/x+4.8]
  solving we get x=1.6
  so, the length of shadow is 1.6m
• 12 years agoHelpfull: Yes(0) No(0)