How Does Magnification Change When Switching from Convex to Concave Mirror?

[gamesandmore]

A spherical mirror is polished on both sides. When used as a convex mirror, the magnification
is +1/4. What is the magnification when used as a concave mirror, the object remaining the
same distance from the mirror?

I started with:

mconvex = 1/4
mconcave = ?

doconvex = doconcave
hoconvex = hoconcave

I wasn't sure about how to go from here...:

m = hi/ho = -di/do

mconvex = hiconvex/hoconvex = -diconvex/doconvex
mconcave = hiconcave/hoconcave = -diconcave/doconcave

1/4 = hiconvex/hoconvex
hoconvex = 4hiconvex

mconcave = hiconcave / hoconcave
hoconcave = hiconcave / mconcave

4hiconvex = hiconcave / mconcave

mconcave = hiconcave / 4hiconvex

I wasn't sure what to do from here or if I approached this correctly

 

[mgb_phys]

This probably does a better job of drawing the diagrams than I could.
https://www.math.ubc.ca/~cass/courses/m309-01a/chu/MirrorsLenses/mirror-calcs.htm

Basically it's just a matter of getting the signs for the focal length correct.