What is x when 72 divided by x equals 90?

To find the answer, just divide the dividend by the quotient: 72 ÷ 90 = 0.8

To prove this, let's compute 72 divided by 0.8: $\frac{72}{0.8} = 90$

How does it work?

Asking what the value of x could be when 72 divided by x gives a result of 90, is equivalent to solving the following equation:

$\frac{72}{x} = 90$

Multiply both sides by x: $\frac{72 x}{x} = 90 x$
$\frac{72 x}{x}$ is equivalent to $\frac{x}{x} \times 72$ , which simplifies to $1 \times 72$ (or just $72$ ).
Thus, the equation becomes: $72 = 90 x$
To find x, divide both sides by 90: $\frac{72}{90} = \frac{90 x}{90}$
Which gives, after simplification: $0.8 = x$ (or $x = 0.8$ )

So, if the dividend is 72 and the quotient is 90, the divisor is 0.8.