Calculating Distance from Mirror for Virtual Image Height of 1.145 cm

[I_LuV_FiZiX]

Homework Statement

An object whose height is 0.375 cm is at a distance of 10.5 cm from a spherical concave mirror. Its image is real and has a height of 1.145 cm. Calculate the radius of curvature of the mirror.

Correct, computer gets: 1.58e+01 cm

ACTUAL QUESTION
How far from the mirror is it necessary to place the above object in order to have a virtual image with a height of 1.145 cm?

Homework Equations

1/S + 1/Si = 2/R = 1/f
Hi/H = -Si/S

The Attempt at a Solution

I am not sure how to relate the equations...Also, I am unsure as to how the image being virtual in the actual question changes things. I know f=R/2 = 7.9cm

Homework Statement

 

[rl.bhat]

Using Hi/H = -Si/S find S in terms of Si. Put it in the equation 1/S + 1/Si = 2/R = 1/f with proper sign of S, Si and f. Solve for S.