A high school student studying optics finds that the focal length \(f\) of a lens is related to object and image distances by \( \frac1f = \frac1d_o + \frac1d_i \). If \(d_o = 30 \, \textcm\) and \(d_i = 60 \, \textcm\), what is \(f\) in cm? - Crosslake