If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Using the magnification formula for mirrors

You might need: Calculator


As shown in the diagram below, an object O of height 3.0 cm is kept in front of a concave mirror, which forms the image I.
Find the height of the image hI.
Note: Let's write the answer in the Cartesian sign convention.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi