Page 1 :
A girl looks the reflection of the top of the lamp post on the mirror which is 66 m, away from the foot of the lamppost. The girl whose height is 12.5 m is standing, 2.5 m away from the mirror. Assuming the mirror is placed on the ground facing, , the sky and the girl, mirror and the lamppost are in a same line, find the height of, the lamp post., , Solution :, , Given : In the fig. AB represents the Lamp post ; DE represents the Girl., , , , , , AC =66m; CD=2.5m; DE=12.5m ,, In the triangles ACB and DCE,, The angle of incidental ray = The angle of reflected ray, ACB = 2DCE E g, Being perpendicular to the ground 2CAB = ZCDE = 90° §, BY AA criteria, A ACB~A DCE &, Ap _ AC g, DE oc, Ma; ap=22*-330m 90 55m am A, , Height of the lamp post (AB) = 330m