What is x when 10 divided by x equals 21?

To find the answer, just divide the dividend by the quotient: 10 ÷ 21 = 0.47619047619048

To prove this, let's compute 10 divided by 0.47619047619048: $\frac{10}{0.47619047619048} = 21$

How does it work?

Asking what the value of x could be when 10 divided by x gives a result of 21, is equivalent to solving the following equation:

$\frac{10}{x} = 21$

Multiply both sides by x: $\frac{10 x}{x} = 21 x$
$\frac{10 x}{x}$ is equivalent to $\frac{x}{x} \times 10$ , which simplifies to $1 \times 10$ (or just $10$ ).
Thus, the equation becomes: $10 = 21 x$
To find x, divide both sides by 21: $\frac{10}{21} = \frac{21 x}{21}$
Which gives, after simplification: $0.47619047619048 = x$ (or $x = 0.47619047619048$ )

So, if the dividend is 10 and the quotient is 21, the divisor is 0.47619047619048.