So I originally posted a thread for my optics homework listing every question from a worksheet AND my attempts. Apparently, it's seen as spam so I have tried and am now posting the second question. 1. The problem statement, all variables and given/known data A concave mirror has a focal length of 40 cm. Determine the object position for which the resulting image is upright and four times the size of the object. Construct a ray diagram for this situation. GIVEN DATA Focal length= 40 c.m 2. Relevant equations (1/do)+(1/di)=1/f 3. The attempt at a solution I can't really attempt it because I barely have any information. How can I determine the object position with only the focal length. And what exactly are do and di?