Answer
$R=219~\Omega$.
Work Step by Step
Given
$\frac{1}{R}=\frac{1}{R_{1}}+\frac{1}{R_{2}}+\frac{1}{R_{3}}$+\frac{1}{R_{4}}
$R=?, R_{1}=655~\Omega, R_{2}=775~\Omega, R_{3}=1050~\Omega,
R_{4}=1250~\Omega$
$\frac{1}{R}=\frac{1}{655}+\frac{1}{775}+\frac{1}{1050}+\frac{1}{1250}$
Therefore, $R=218~\Omega$
How to use the calculator:
$655*x^{-1}+775*x^{-1}+1050*x^{-1}+1250*x^{-1}=x^{-1}=$
