Mixed Format $$E _ { L I N E } = \sqrt { E_ R ^ { 2 } + E_ X ^ { 2 } }$$

Short Answer

Mixed format: $$E _ { L I N E } = \sqrt { E_ R ^ { 2 } + E_ X ^ { 2 } }$$ (with a space between the whole number and the numerator) Fraction format: $1 /4$
Reduce all fractions. A motor brush is $$\begin{aligned}Z = \frac { E } { I } \quad \text { where } & Z = \text { impedance in ohms } \\& E = \text { voltage in volts } \\I & = \text { current in amperes }\end{aligned}$$ inches long. How long is it after $49 / 64$ wears away?