which is 0.8m above the ground. the length of image he see is ???

In the figure GH(mirror)=0.3m

AF =1.5m

DF=0.8m

In the figure GH is mirror

                          IJ is image

                          AF is the man

Bottom most point that can be seen from the mirror is E

 DA=DE=1.5-0.8=0.7m

EF=1.5-2*0.7=0.1m

Uppermost point that can be seen from the mirror is C

AB=BC=1.5-(0.8+0.3)=0.4m

So the portion that can be seen is CE

CE=AF-EF-AC

  =1.5-0.1-2*0.4=0.6m

Easier method

Extend IH

IH = HD

in triangle IAD

HG ll AD

IH = HD

therefore ,G is midpoint of AI

THEN

I triangle AIJ







G is midpoint of AI







H is midpoint of AJ

Therefore , I J = 2 GH (midpoint theorem )







IJ = 2 * 0.3 = 0.6 cm