# Homework Help: An image is magnified by 2.50, concave mirror confusion! wee

1. Mar 14, 2006

### mr_coffee

Hello everyone< i think i'm on the right track but now i'm stuck.
Here is the problem:
A concave shaving mirror has a radius of curvature of 37.0 cm. It is positioned so that the (upright) image of a man's face is 2.50 times the size of the face. How far is the mirror from the face?

Here is my work and drawing:
http://suprfile.com/src/1/6mwvik/lastscan.jpg [Broken]

I'm conufsed on how i'm suppose to find the object distance if i'm not giving the image distance.

Last edited by a moderator: May 2, 2017
2. Mar 14, 2006

### Chi Meson

Simultaneous equations. You have both of them. Two unkowns, di and do.

3. Mar 14, 2006

### stunner5000pt

like he said
instead of using the hi-ho (:rofl:) relation find a relation between di and do.

sub into your lens equation and you're all set.

4. Mar 14, 2006

### mr_coffee

Awesome thanks alot guys worked great!
11.1cm for object distance, o yes!