#### Answer

Answer: $Reciprocals$

#### Work Step by Step

$\frac{x}{2y}$ and $\frac{2y}{x}$ are reciprocals.
A reciprocal of any nonzero fraction is 1 over that fraction.
Reciprocal of $\frac{x}{2y}$ = $\frac{1}{\frac{x}{2y}}$ = $\frac{2y}{x}$.
(For the reciprocal of a nonzero fraction, exchange the numerator with the denominator and the denominator with the numerator.)
Also, the product of the reciprocals is always = 1:
$\frac{x}{2y}$ $\times$ $\frac{2y}{x}$ = 1 .......(Since $\frac{x}{x}$ = 1 and $\frac{2y}{2y}$ =1).