a 9 cm high image of object formed on screen by convex lens when lens displaced towards screen again - Physics - Ray Optics And Optical Instruments

Question

a 9 cm high image of object formed on screen by convex lens when
lens displaced towards screen again 4cm high image formed on screen
what is the high of object?

Ved Prakash Lakhera · Accepted Answer

According to diaplacement method:size of object, O=I1I2where I1 & I2 are the size of imagesO=9×4O=36=6 cm

a 9 cm high image of object formed on screen by convex lens .when lens displaced towards screen again 4cm high image formed on screen .what is the high of object?