What is x when 42 divided by x equals 4?

To find the answer, just divide the dividend by the quotient: 42 ÷ 4 = 10.5

To prove this, let's compute 42 divided by 10.5: $\frac{42}{10.5} = 4$

How does it work?

Asking what the value of x could be when 42 divided by x gives a result of 4, is equivalent to solving the following equation:

$\frac{42}{x} = 4$

Multiply both sides by x: $\frac{42 x}{x} = 4 x$
$\frac{42 x}{x}$ is equivalent to $\frac{x}{x} \times 42$ , which simplifies to $1 \times 42$ (or just $42$ ).
Thus, the equation becomes: $42 = 4 x$
To find x, divide both sides by 4: $\frac{42}{4} = \frac{4 x}{4}$
Which gives, after simplification: $10.5 = x$ (or $x = 10.5$ )

So, if the dividend is 42 and the quotient is 4, the divisor is 10.5.