What is x when 81 divided by x equals 16?

To find the answer, just divide the dividend by the quotient: 81 ÷ 16 = 5.0625

To prove this, let's compute 81 divided by 5.0625: $\frac{81}{5.0625} = 16$

How does it work?

Asking what the value of x could be when 81 divided by x gives a result of 16, is equivalent to solving the following equation:

$\frac{81}{x} = 16$

Multiply both sides by x: $\frac{81 x}{x} = 16 x$
$\frac{81 x}{x}$ is equivalent to $\frac{x}{x} \times 81$ , which simplifies to $1 \times 81$ (or just $81$ ).
Thus, the equation becomes: $81 = 16 x$
To find x, divide both sides by 16: $\frac{81}{16} = \frac{16 x}{16}$
Which gives, after simplification: $5.0625 = x$ (or $x = 5.0625$ )

So, if the dividend is 81 and the quotient is 16, the divisor is 5.0625.