What is x when 38 divided by x equals 21?

To find the answer, just divide the dividend by the quotient: 38 ÷ 21 = 1.8095238095238

To prove this, let's compute 38 divided by 1.8095238095238: $\frac{38}{1.8095238095238} = 21$

How does it work?

Asking what the value of x could be when 38 divided by x gives a result of 21, is equivalent to solving the following equation:

$\frac{38}{x} = 21$

Multiply both sides by x: $\frac{38 x}{x} = 21 x$
$\frac{38 x}{x}$ is equivalent to $\frac{x}{x} \times 38$ , which simplifies to $1 \times 38$ (or just $38$ ).
Thus, the equation becomes: $38 = 21 x$
To find x, divide both sides by 21: $\frac{38}{21} = \frac{21 x}{21}$
Which gives, after simplification: $1.8095238095238 = x$ (or $x = 1.8095238095238$ )

So, if the dividend is 38 and the quotient is 21, the divisor is 1.8095238095238.