What is x when 78 divided by x equals 80?

To find the answer, just divide the dividend by the quotient: 78 ÷ 80 = 0.975

To prove this, let's compute 78 divided by 0.975: $\frac{78}{0.975} = 80$

How does it work?

Asking what the value of x could be when 78 divided by x gives a result of 80, is equivalent to solving the following equation:

$\frac{78}{x} = 80$

Multiply both sides by x: $\frac{78 x}{x} = 80 x$
$\frac{78 x}{x}$ is equivalent to $\frac{x}{x} \times 78$ , which simplifies to $1 \times 78$ (or just $78$ ).
Thus, the equation becomes: $78 = 80 x$
To find x, divide both sides by 80: $\frac{78}{80} = \frac{80 x}{80}$
Which gives, after simplification: $0.975 = x$ (or $x = 0.975$ )

So, if the dividend is 78 and the quotient is 80, the divisor is 0.975.