What is x when 53 divided by x equals 21?

To find the answer, just divide the dividend by the quotient: 53 ÷ 21 = 2.5238095238095

To prove this, let's compute 53 divided by 2.5238095238095: $\frac{53}{2.5238095238095} = 21$

How does it work?

Asking what the value of x could be when 53 divided by x gives a result of 21, is equivalent to solving the following equation:

$\frac{53}{x} = 21$

Multiply both sides by x: $\frac{53 x}{x} = 21 x$
$\frac{53 x}{x}$ is equivalent to $\frac{x}{x} \times 53$ , which simplifies to $1 \times 53$ (or just $53$ ).
Thus, the equation becomes: $53 = 21 x$
To find x, divide both sides by 21: $\frac{53}{21} = \frac{21 x}{21}$
Which gives, after simplification: $2.5238095238095 = x$ (or $x = 2.5238095238095$ )

So, if the dividend is 53 and the quotient is 21, the divisor is 2.5238095238095.