Question

A girl of height 90 cm is walking away from the base of the long bulbs put poll at a speed of 1.2 m/s. If bulb is put at the height of 3.6 m above the ground find the length of her shadow after 4 min??

Answer 1

If your question is:

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

Then the solution is:



Let the girl be at point D on the ground from the lamppost after 4 sec.

∴ AD = 1.2 m/sec × 4 sec = 4.8 m = 480 cm

Suppose the length of the shadow of the girl be x cm when she at position D.

∴ CD = x cm

In ∆CDE and ∆CAB

∠CDE = ∠CAB  (90°)

∠DCE = ∠ACB  (Common)

∴ ∆CDE ∼ ∆CAB  (AA similarity)



 

∴ Length of her shadow after 4 second is 160 cm

Answer 2

Answer:

Step-by-step explanation:

solution is:



Let the girl be at point D on the ground from the lamppost after 4 sec.

∴ AD = 1.2 m/sec × 4 sec = 4.8 m = 480 cm

Suppose the length of the shadow of the girl be x cm when she at position D.

∴ CD = x cm

In ∆CDE and ∆CAB

∠CDE = ∠CAB  (90°)

∠DCE = ∠ACB  (Common)

∴ ∆CDE ∼ ∆CAB  (AA similarity)



 

∴ Length of her shadow after 4 second is 160 cm