Answer
$R_{1}=44.5~cm$
Work Step by Step
Given
$\frac{1}{f}=\frac{1}{S_{0}}+\frac{1}{S_{i}}$
$f=14.5cm, S_{0}=21.5cm, S_{i}=?$
$\frac{1}{14.5}=\frac{1}{21.5}+\frac{1}{S_{i}}$
$\frac{1}{S_{i}}=\frac{1}{14.5}-\frac{1}{21.5}$
Therefore, $R_{1}=44.5~cm$
How to use the calculator:
$14.5,*,x^{-1},-,21.5,*,x^{-1},=,x^{-1},=.$
