Finding image location with concave mirror

[physiquephys]

Homework Statement

A small object is located 32.0cm in front of a concave mirror with a radius of curvature of 40.9cm.
Where will the image be formed?

Homework Equations

tan(θ)=-h/di
f=1/2R?

The Attempt at a Solution

Haven't been able to solve for theta. I'm not sure what equation to use, but I'm guessing that the radius is important. Do I need to find the focal length?

 

[Redbelly98]

Welcome to Physics Forums.

Yes, you need to find the focal length first. And, your textbook should have a formula that relates focal length to the positions of the object and image, that will be helpful here.

 

[Emilyjoint]

you do need to know the focal length. You have to be careful with equations. focal length =R/2 not...1/2R...do you see what I mean/

 

[physiquephys]

Ohhhh, I see. I use 1/do + 1/di = 2/R (which is the focal point, & the reason the difference is indicated). Thank you both!

 

[Redbelly98]

Yes, that's the idea. You're welcome!