a man 1 5m tall walks away from a lamp post 4 5m high at the rate of 4km/hr - Maths - Application of Derivatives

Question

a man 1 5m tall walks away from a lamp post 4 5m high at the rate
of 4km/hr

how fast the farther end of the shadow moving on the
pavement

Kundan Singh · Answer

take tan x =height of man /size of shadow
and tan x=height of lamp/size of shadow + distance between man and
lamp

then equate it you will get the answer as 2km/h

a man 1.5m tall walks away from a lamp post 4.5m high at the rate of 4km/hr. how fast the farther end of the shadow moving on the pavement