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## Homework Statement

With a lens with f = 25 cm, we want to project an image that is 5 times bigger than object, so M = 5

- Find the image distance s'

- Find the image height Hi

## Homework Equations

1/f = 1/s + 1/s'

M = s'/s = Hi/Ho

With:

f = focus distance of lens

M = magnification

s' = image distance

s = object distance

Hi = image height

Ho = object height

## The Attempt at a Solution

From the second equation we get: 1/s = M/s'

Substitute that in first equation to get s':

1/f = M/s' + 1/s' --> s' = (M+1)f = (5+1)*25 = 150 cm

The problem is now i don't know how to get the image height...from our answer we can easily calculate that s = 30 cm, so we know:

M = 5

f = 25 cm

s = 30 cm

s' = 150 cm

how do i get Hi?